Film cameras can be so so cheap, but be prepared to give them a little love and attention. Anything much older than 20 years, be prepared to change the light seals. It's usually a fairly cheap and easy job to do yourself. Check lenses for fungi.
I have two digital SLR cameras, but I also use film cameras. 35mm film is still easily available and can be cheap. I pay £1 for AgfaPhoto Vista Plus films (77 US cents). Getting them developed can be more problematic, but there are still many local independent processors with a photolab machine, and if not, many postal developers. Lots of people however opt to shoot in true b&w and then develop themselves. Either way, it's worth buying a digital scanner. Many flatbeds have film masks, and lamps built into their lids, to scan negatives or slides. Then all you need is the negatives.
120 roll film is still available, but if you think that you will ever use it, try invest in a digital scanner that can scan 35mm or 120 film negatives. Again, 120 b&w negatives can be developed at home.
As for price, I find Ebay a little expensive. The cheapest places here in the UK are 'car boot sales' - sort of mass yard sales. Examples of working film cameras that I've bought over the past twelve months:
Pentax ME Super - £10 from Ebay
Olympus Trip 35 - £5 from a car boot sale
Olympus XA-2 - £0.50p from a car boot sale (38 US cents)
Kodak Retinette 2A - £2 from a car boot sale
Lubitel 166B TLR - £2 from a car boot sale (yes, I paid less than a few dollars for a medium format film TLR!)
You get the drift, they are VERY cheap, just be prepared to clean them up and replace light seals, which can be purchased online. Film is not as 'instant' or convenient as Digital, but it is a whole lot of fun, and worth enjoying while it's still around.