+1000 been there, done that. While building up your own bike is fun, it is much more expensive than buying a complete bike. I bought a Raleigh Sprite complete bike for $100 and spent another $500 or so converting it to my liking. Awesome looking bike, fun to ride. But for that money, I could've bought a nice, new bike with plenty of cash leftover. Same for my wife's singlespeed. Started with a $25 Peugeot frame, don't even want to total up what I poured into it.

Bikesdirect.com is your budget bike buddy. Or you may get lucky on Craigslist but only if you know what you're looking for. Or looking at. Same for garage sales. You can score killer deals but it takes a lot of time and effort.

Best to get rolling on a Kilo and increase your bicycle knowledge by hanging out here. The Classic and Vintage forum is also good for learning about older, used bikes. Lots of flippers there giving out lots of good advice.

Also, be sure to read Sheldon Brown-Bicycle Technical Information