Well, $250 isn't going to buy you much in the way of a new bike. Used, maybe. But not new. The good thing is there is a pretty good range of bikes available around the $500-600 mark. I know that's a little higher than you are looking to spend, but you really don't want to be riding around on a bike that retails for $250. They are often assembled unsafely, and use very cheap parts that won't last very long. I have seen many people go to Wal-Mart or somewhere and buy a cheap bike only to give up riding all together within a few weeks because the bike won't shift, or doesn't ride well.

Go to Just The Right Gear, East Coasters, Cardinal, or Peddler and have them fit you on the bike. They will let you try out many different models and sizes to see what fits you. It's not a one-size-fits-all thing. Getting on a bike that fits you correctly is the single most important thing. In fact, I'd much rather ride a $500 bike that fits than a $5000 bike that is too big or too small.

I'm actually in the market for a new bike right now and getting ready to do some shopping. If you want, I'll be glad to go with you and point you in the right direction.