You can check out this sticky or looking around on this forum - lots of stories on how people have done this:

http://www.bikeforums.net/showthread.php?t=473408

Also, to be clear, if you do some research on how to evaluate used bikes (or take a friend along), you won't really have to buy new components. The expensive components - wheels, derailleurs, crankset, etc. should be just fine.

But the classic used bike is a bike someone bought some years ago, rode for a couple of seasons, and put it away. They might have stopped riding because they were frustrated that it needed a mild tune-up, and then in storage the tires went flat.

When *you* buy it, all you have to replace is the (relatively cheap) wear items - tires, tubes, brake pads, for starters. Might need new cables, might not.

A *huge* percentage of bikes sold in America never get ridden over 500 miles. That's what you're looking for.