Check out this PetaPixle article on choosing an older film camera / lens.
What to check for on an older camera.

Quick questions: 1. does the camera work ?
35mm: Battery case is clean, you can wind and fire (some need batteries to fire), rewind knob is there, the back opens and foam edge is not sticky, battery cover and rewind knob is there (no replacements, impossible to find for any make).  Light meter working ? (battery ?)

Late folding models: they can take 35mm film, lens is clean, shutter fires (usually you can fire multiple times with no film), film area is clean.

2. Older Folding:  Type of film available (only 120, 620 (can make 120 work), 127 (Kodak Vest Pocket) is very expensive, and 828 (Kodak Bantam's and Pony) film is very expensive , 116, 616 film: can use 120 with adapter. 
Lens is clean, bellows is good - no tears - no pin holes, shutter works (you have to load it, then fire), film area is clean.

35mm cameras (60s, 70s to 2000)
1. If you found an old 35mm from your parents/uncle or want to use one, there are many 60s to 2000s camera available.  If you buy one used, how do you know it will work.  Hopefully the camera has been used in the page 4 years.  If not the batteries to run it or the battery in the meter may have leaked.  All those batteries that run the newer auto focus cameras are still available.  If the camera turns on, a big step forward.  Some of the older cameras that use AA batteries may need cleaning on the battery terminals.  If the contacts are badly rusted, problems already.  A pencil rubber end with sandpaper glued to it can help.  Depending on the age of the camera, the light meter is the only battery.  If you have a early 70s camera, they may take a mercury battery.  There are Wein Air Batteries that will replace them for pretty cheap. Get a few, they only last 4 - 6 months.  The old cameras had power winders, again AA batteries and possible bad contacts.
Sorry to say if a 35mm camera is dead...it's gone.  Many need to be powered to fire, if the electronics are bad that's usually it.  Older electric meter only cameras will work without batteries but you can use them without the meter system.  If the camera needs a battery to fire, you may just need a new battery with cleaned contacts.  Older non battery camera that won't wind, big problems.

APS cameras:  They came out in 1996 - the batteries for the cameras are still available.  For some reason the film is still available, but I read Kodak and Fuji dropped APS in 2011.  You can find processing places on the web, but that is a different machine then 35mm film.  So how long they will keep running them is anyone's guess.

2. The light proof back of the older 60s to 80s camera were foam.  That is the foam in the edge of the back body.  Some may be fine, others may have turned to mush.  There are ways to replace it, it is messy, not too expensive because you have to do the labor.  Replacement foam and instructions are available on-line.

3. Film should be no problem, if you can still find 35mm film and processing.  If you Google, you can find the harder part, someone to process it.  Most drug stores just send the film out, back in a few days.  WARNING: some processing places are only scanning and sending you a CD or location were you can download the images.  Some processing places will scan then destroy the your negs.
There are lots of places doing film processing on-line, and may follow the above warning.

4. Lenses are another problem.  If they were stored in high humidity, fungus can attack the lens. Open the aperture and look through it at light.  Fine lines in a circular pattern, you have a fungus.  Photos will be blurry.  Plus check the aperture, it should snap back quickly.  The lens or zoom should turn smoothly.  A dropped lens with a bent front may be hard to turn.  It will work, but there is no economical way to fix it.  Ebay and various on-line camera stores have thousands of used lenses.

Cartridge Cameras:
Yes, they still make film for these, not sure why.  The instamatic cameras were made by every company.  There is another film make called RAPID.  It was out for a couple of years trying to compete with the cartridge film. Guess who won.  Too bad, as many of these cameras have very good lenses and automation.  Still the RAPID film never caught on.  It was 35mm film in a special cartridge.  Those 127 and 110 cameras were never made well or with quality lenses.  It would be a waste of money to try to revive them.  There were a FEW that had decent lenses and automation.  A couple 110 camera actually came out with interchangeable lenses and highly automated.  Pentax 110 and Minolta 110 which only had a zoom lens attached.

Instant Cameras:
Yes, due to the "Impossible Project" they found a way to make instant cartridge film as well as other instant film.  It'll cost you, but a SX-70 can come alive again.  You can go way crazy and buy a refurbished SX-70 from a few places.  Fuji just came out with an instant camera... old is new again !  And they sell film too.  As of 2017 Polaroid is under new owners and is selling a new (old model) One Step-2 instant camera.  Film is currently $9 for 8 shots.  One of the founders of the "Impossible Project" bought out all the Polaroid licenses and intellectual property in 2017.

Disk Camera:
Forget them, they were not good to start with.  Yea, there are places that will process it if the film is found in a camera.  No guarantee anything will come out.  Film is no longer available for this size.

Older cameras and those not taking 35mm film - click here for adapters for older cameras to take current film.  Also...see bottom of page.

1. FOLDING CAMERAS
I am now talking about your grandparents camera. 
Folding types.  There are small Kodak and other folding cameras that take 35 film.  The problems with them are their age.  The bellows (if it has them) will most likely be brittle.  If they have cracks in them or pinholes, you will have ruined film.  Again, the light sealing material needs to be working around the film door.
Lenses that are clear and a shutter that is still working after some 40+ years are a positive.  Years of dust on the inside/outside of these lenses can be cleaned with Windex and a swab if needed.  Almost none of these lenses are coated.   Many of these folding cameras have a specific way to close them, hence my PDF files to assist you on that.  Be aware, that if the shutter does not work, check the manual as they may have some strange behaviors.  But again, 30, 40 60+ years with many users or just age can cause these simple shutters not to work.

Standard folding camera start from the first cameras to the 1950s.  Except for the "box" cameras.  The first thing you have to realize, there were no "enlargers" at the printing companies way back when.  So the size of the negative is the size of the print.  They were "contacted printed" the negative against paper.  A one to one relationship.  So the bigger the image, the negative had  to be the same size hence these gigantic size cameras because the prints were bigger.  Some of the cameras took 120 film, still available.  Then there is 620 film, no longer readily available but check on-line for ways to make a 120 roll film fit a 620 camera.  This method may not work in very 620 camera. It's not that hard and you still have the easy and ability to shoot and process standard 120 film.  May other variations of large film were used.

NO AUTOMATION:
These camera are rocket science to operate !  No automation at all.  You must figure out the shutter and aperture depending on the film speed.  Old films used for these camera were terribly slow, like 10 ASA.  Current films are 100 ASA, 200 ASA and even 400 ASA.  These cameras had slow shutter speeds, due to the old film speeds as well as the shutter being just a spring.  So a standard exposure in full sunlight is the ASA of the film at F16.  This can be easily adjusted for different setting and get the same exposure to the negative.  Hopefully you have F-stop settings.  Some camera have their own lens numbers, back to searching on the net to figure them out.  So the old 10 ASA is 1/10 at F16, or 1/20 at F11 or 1/40 at F8, all giving the same exposure.  But with modern film ASA 100  is 1/100 at F16, 1/50 at F22 or 1/25 at F32 or 1/15 at F64.  Slower shutter, smaller aperture.  Faster shutter, wider aperture.

Most older folding cameras can barely get to 1/100 sec exposure, so the fast film can be a problem. Forget ASA 200 or ASA 400 film.  Exposures in clouds 1/100 at F11,  heavy shade 1/100 at F8. After you figure out the crazy exposure, you must figure out the accurate distance to the subject, bring a ruler !  You then turn the front of the lens to the correct distance.  Or there is a scale on the slider bar where you physically move the camera from closer to the film or further away to focus.  Since you are allowed fast film, you're not shooting at 1/8 of a second trying to hold the camera very steady.  If not, you'll see the blurry images from your grandparents photo album.  After all this fuss, fire the shutter.  Again, some camera you have to wind the shutter, then fire it. You will hear a teeny, tiny click.  Then, did I expose this frame or not.  ALWAYS wind to the next frame after you shoot.  If your camera has the right film, you can wind to the next frame by using that hidden red window.  EASY !  Practice this before trying real film, get used to all the prep.  Then remember, you only get some 8 shots !  Then take out the film, change reels, load, wind to #1.  Rocket Science !

2. BOX CAMERAS
Kodak as well as others made box cameras.  Very simple, many used 120 film.  Some use other types no longer made without paying $18 a roll.  You can find non standard film on line, just be wary the costs will be high.   And technology comes to the rescue, a 3D printer has allowed people to make adapters that will make 120 spools fit the spaces and different film ends fit these cameras.  You can find these adapters on-line by searching for "spool adapters".

3. Cameras with film no longer available.
Very old cameras up to 1902, each camera had it's own film and film size.  This is where Kodak made their mark by just having a few sizes of film for all of their cameras.  These outdated film sizes includes 616, 116, 620, 127, 828, 101, you have the possibility of using 120 film with adapters or you can buy these films from special places that serve needy photographers.  All the other film sizes on the link above will have a very difficult time getting something to work.  This does not means people haven't tried, but they are very knowledgeable about photography and had to try many rolls to get images to come out.
Older cameras did not have any automation, when you pressed the shutter, you had to turn the film spool knob until the red window on the back showed the next exposure number.  Even cameras that used 120 had different negative sized.  These exposure numbers were printed on the back of the paper that held the film.  On 120 the frame numbers were printed in different areas, so And with adapters or completely different film, these numbers will not match up.  So a lot of guess work has to be done as you are working blind to wind the film to the next blank spot on the roll.  If not you will get overlap of images.  With cameras that need "guess work" to find the next blank frame many places will suggest to wind extra.  This way you will not overlap, but if you were suppose to get 10 shots, you will only get 8 or so while leaving lots of space between frames.

There is a lot of information out there to help if you want to use a film camera or older folder / box camera.  If it uses film you can find, that is a big help. There are a lot of cameras that used 127 and 828 film.  If $18 for film plus processing is fine, you can give it a try and see just how the grandparents did it in the "old days".  A number of film only web site have popped up and good old Google can help you find an awful lot of information.

Good Luck !

Your Go-To sites
If you find any more - tell me.

The frugal photographer - common and strange films

Drug stores - They will process many modern films for cheap

Ritz Camera - film and processing

The Darkroom

Places for non-standard film -
Films for Classics is working with B and H Photo in NYC

Making 120 film fit a 620 camera
Just a Google listing
You can BUY 620 film for some $18 a roll

Kodak Classic website
Help on getting film to fit various Kodak cameras
Like 616 or 828 film
You can now buy a 616 film adapter pretty cheap - Amazon / Ebay

116 / 616 film

You can try this site, it sells adapters for 120 to fit in older cameras
Remember you have to wind past the standard numbers as these negatives are larger.
CameraHacks.com


Dayton Batteries

B&H photo and Video (closed Saturdays)

Old School Photo Lab
Weird films developed - they returns negs

Instant cameras
There are now a variety of instant film sizes and cameras
Amazon, E-bay, just Google it

If you found old film and really want to try
to find out what's on it.  The only place to really try.
It may cost ya, It'll take lots of time, but this is their specialty - Film Rescue.

Film cameras for "artsy prints"
Square images, pin hole, printing film sprockets
Holga (closed) or Lomography

Back to my Camera Manual Page - www.butkus.org/chinon

Back to my main information page - www.butkus.org