Pentax K1000
I have to confess that I’m a huge fan of Pentax 35mm cameras—I have 3 of them (including the K1000). They’re well-built, easy to use and the Pentax K1000 was especially popular. If you took a photography class in the mid-to-late 1970’s (and beyond), you probably used a K1000. It was affordable and had all the basic features you needed to learn about making pictures (and practice manual focus).

By the way, if you happen to have some old Pentax screw mount lenses (or buy them with the K1000), you can use them on a Pentax digital SLR with an adapter. Plus, you can't beat the price.

Sample Prices:

KEH: starting at $47 (body only)
Ebay: starting at $50 (body only)
Craigslist: $40 (with Sunpak flash, case and neckstrap)