I got a bike at a flea market yesterday! It was only 30 Euros and a real piece of junk, but totally usable, which is exactly what I was looking for.
It's not quite as bad as the photo above, but a shit-bike never the less. The idea is that if it's super shitty, it will be less likely to be stolen. Berlin is a huge bike-theft town, which is why I almost never ride my über-nice Felt bike around. It would be gone the instant I turned my back to it. So now I have a bike I can actually leave chained up somewhere and be fairly confident it will still be there when I get back. Sweet! It tends to shift gears of it's own volition, but so be it. At least it has decent breaks and a seat.