Hello, I am hoping to purchase a used road bike. I found a decent looking one on sale on craigslist, but the seller cautioned me that the bike cannot chage the gear, although it's rideable. He says that it only costs 20 bucks to fix it. Is this true?

It will depend on what sort of shifter the bike has, and what needs to be done to it. A broken shift cable would cost under $20 to repair, a worn out SDI Brifter might cost $200 for the parts.

If you don't know a lot about bikes, you will be much better off buying a bike from a bike shop rather than craigslist or a department store. You will get better quality, and someone who can help you determine if it is the right bike for you.

If I didn't know much about cars and I wasn't able to buy a new one from a dealer I might get a friend who does know something about bikes to look over my purchase. I've had pretty good luck with Craigslist and if the guy says $20 will do it I don't have enough paranoia at the moment (it's not my money) to say it wouldn't. It's a bicycle. Unless something is bent, broken or missing... ... I could get even more emphatic, use bold type even if you had mentioned make and model (and year) of bike and the asking price.

H