Best bet would be a TLR. This isn't an
SLR but it's the most risk-free and least expensive entry point into medium format. A Yashica Mat would arguably be the best price/performace option. There are scads of TLRs up on the auction sites. I've never owned a TLR but they take
great pictures, are far less bulky that the medium format SLRs - of which you have few options and are more expensive. You can most definitely get a serviceable one in the $100 range.
If you must have an SLR by far the least expensive is the Kiev 60. They go for around $100 - prices vary (and you get what you pay for), and do note these almost always come from overseas and shipping is expensive. In searching eBay it seems sellers overseas are no longer including the Volna 80mm kit lens - just the body, which wasn't the case when I bought mine 6-7 years ago... so figure $100 for a starter Kiev lens - any will be fine. (However, I didn't see a single Volna 80mm lens up. Hmmm. Weird.)
Another Option is the Pentacon 6. These are older that the Kievs but take the same lens mount. Here's an auction
with a lens for one of these
http://cgi.ebay.com/Rusian-camera-K...ilm_Cameras&hash=item5d27d67aec#ht_5977wt_930 for $119 but do not that shipping is over $60.
Folders - great in concept, smallest easiest to carry around but I went through my "folder oddesy" - buying, fixing several until I finally got one - an Iskra, that worked fine (that I sold...). I don't do medium format at the moment, but plan on getting back into it with either one of the automatic Fuji "point-n-shoot" or a TLR (probably a TLR).
As someone who's "been there, done that"
1. Kievs are the "most reliable" but they're wonk-y. Although mine worked perfectly, it always felt fragile. Like all MF SLRs, it's HUGE. You will get tired of carrying it around and getting weird looks if using it out and about. It's also quite ugly. However, it takes great pictures.
2. Folders are old and fragile. They get light-leaks, often in the bellows, and most are scale focus, which I hate. Apart from this, they're a little "too manual" and "too low-tech" for my taste.
You can get into 35mm film photography dirt cheap. Some auctions for decent 35mm cameras go begging w/ no bidders, or you can get a decent kit at a yard sale for next to nothing...
This is not true with medium format. As someone who's "gone the cheap route" (as I do with most things...) If I was to "do over" I would saved myself the time and effort and simply saved up more dough, held out, and got a newer decent camera - probably one of the Fujis that go for around $400-500, or with a TLR in good condition for $100 - $150 (or less). Don't knock the TLR - the staple of wedding photographers worldwide from the 60's through the 90's (some even today...). They knew what they were doing...
And as sonofdanang points out - be patient, esp if you're on a limited budget. I've watch a ton of auctions and save searches on eBay... even when I'm not planning to buy anything. (And I always SNIPE. So sue me... You
have to Snipe. It's the way it's set-up...) I've seen great deals - things falling through the cracks, that I say "dang" that went cheap. I've "stole" some things myself. This is the exception but it happens. You have to be patient, you have to watch a lot of auctions, you have to save searches for specfic items you want, and you have to snipe.
