As tptacek says, Jefferson Park is the bang for your buck winner in Chicago. My sister in law just bought for under 200 with a yard, and a decent 2 floor home. House next door was listed for 150 (incredibly small though), and these aren't garbage homes in a bad neighborhood over there.

I'd buy there too if I wasn't planning on leaving this city in the next year or so. Housing prices are not what make me want to leave here, the climate and congestion are.