I bought an old Canon EOS 400D off an auction site for ~$80, which is peanuts comparing to what a new one costs. The only catch was that it was “defect”, without any deeper details of what the defect in question was about.
Having zero experience (both as a user and electronically) of digital system cameras – but always wanting one – I could immediately see that it was indeed defect; it wouldn’t even turn on.
First part of the problem was that the battery was drained, and I had only an old Canon charger incompatible with an EOS 400-battery. Using a homebrew Redneck Adapter(tm) fixed that part.
The second part, the real problem, was that the previous owner had put the CF-card upside down and, with great force, bent nearly all the pins at the connector. They used such great force that one of the pins pried off the PCB.
However, luck was on my side; the pin in question was ground. Finding a ground-plane was easy, so correcting the bent pins and soldering a cable between the loose pin and ground solved everything.
Now I have a great /and/ working DSLR-camera, that I got for peanuts.
Oh, the joy!