Having learned to TIG weld and built a custom frame (under the guidance of a master framebuilder), I've learned:

1) Most of the cost of a bicycle is in the components (read: you're not going to save money by building your own frame)

2) Making money as a frame builder, at least in my area, is difficult or impossible

3) Stock frames fit me fine (read: there's no reason for me to spend big bucks on a custom frame)

Building a frame is a fun project, but I'm not sure that I'd do it again. And I'd certainly never pay for a custom frame made by someone else. Much easier, and ultimately cheaper, to buy a stock bike or at least a ready-made frame.