Yikes! Such negative "build it yourself" energy here...

Go for it man. Yep, it will cost more than buying a complete bike. Yep, it will take some time. Yep, you will need some bike tools. Big deal. Life is short and building up a frame is fun and rewarding.

You can pick and chose the parts you want, where you want the cheaper parts and where you want the better parts. What drive train will work best for you and your situation, the right combo of hubs, rims and tires. The list goes on. You will learn a ton just picking the components. Then you get the experience of the build, learning how your bike is put together and how it all works. Get stumped part way through? Thats where Bike Forums can help. Step back and look at a bike, it is really a pretty simple machine. You will be a better mechanic for it. Gotta buy some tools? Well how are you going to maintain it without some tools?

And do try and buy at least some of your parts from a real live local bike shop.