other options would be thrift stores and pawn shops. like craigslist and other used bikes, there is gonna be garbage out there. One of my previous bikes was a trex from a pawn shop and was an amazing deal.
I hit the local thrift stores on occasion and see amazing good deals there often. a recent example was a very nice Giant hybrid at the local teen challenge. It was 39 bucks. I should have grabbed it up. I went back the next day, with my truck, and cash in hand. it was gone. Two days later it was out front at the lbs, for sale with other used bikes, for 175. Looked like all they had done was put new tires on it. Gone by the weekend.
also, garage sales and local cop auctions