I've always been a tad bit obsessive about checking the used bike listings

I like the idea of recycling and oftentimes, you can find a better quality bikes less expensively (and sometimes real steals!)

Check your local newspaper/craigslist (if you have it) and happy hunting! A word of caution though, many people are unable to accurately measure the size of the bike and ride bicycles not fit to them so I find it useful to provide them with a description. For instance, "What is the measurement from the middle of where the seatpost goes in to where the handlebars attach?"

It's also good to have a second pair of (experienced) eyes to go with you when you see the bicycle whose judgement isn't clouded by the exciting prospect of getting a new bike!