It's definitely possible to get good bikes fairly cheap on CL. My first 'real' bike was a 1988 Centurion Le Mans RS I paid $200 for off CL, it lasted me 7 years until it was stolen last year. I would keep looking if I were you. Just make sure whatever you're looking at is the right size for you, otherwise riding will be difficult and really uncomfortable. There are a lot of good resources online for checking bike size, you should be able to get a decent idea of a size range, and if something's out of that range, you can save yourself a trip!