Originally Posted by goatmeal
I say just go to a thrift store, salvation army, goodwill, whatever. Buy an old bike for pennys (most under 10$ here), either fix it up yourself, or pay your LBS 100$ for the overhaul tune-up. Just steer clear of the same brands of bike you would find at Target, Wallyworld etc, cause they really aren't worth fixing up.
Or even more fun, just convert the bike to SS or Fixed, cause once you get fixed its a irreversable operation.
I can't believe you didn't mention e-bay or police auctions! Trying to keep them off your turf?
Anyways -
If you do go eBay, here's an idea if you don't really know what size you're looking for. Go to a LBS and ask about picking up some lights for your non-existent bike. Tell them that you're broke and looking for a beater on eBay, but don't know exactly you should be looking for. Ask what size range they think you would need, what you'll be using it for, and if they have any recommendations on what brands you could look out for. Let them know that you'll probably be bringing it in once you get it for a tune up.
I think you might end up getting a really good bike that works really well, holds up a long time, quite possibly for around the same price as an X-mart.
It would also help you get to know your LBS, so you would have an idea of what the service is. If they're jerks about spending time with a customer with questions who isn't spending a lot of money, it might not be the best place for you. If they are cool about it and help you out, buy the lights and hit eBay!!!!!