Thanks to both of you for your recommendations. My old bike - which I still have - is a Trek MTB from the early 90s. The front brakes fell off, the tires need replaced, and I'm sure it needs a bunch more stuff than that. I was considering selling it on Craigslist & using the cash toward a new bike. I assumed that it would probably cost more to get the MTB fixed up than to get a new bike, but that may not be the case - I should at least look into it.