Building a bike - good idea or no?

You don't build one from the frame up (new parts) and expect to save money.  If you do used stuff you can compared to buying new, but you could also get a better deal buying a complete used bike from Craig's list or Ebay.

As Pitt said, unless you have all the special tools doing some of the things are a bit complicated.  If you have access to a shop that will let you use the tools, that is one thing that is a plus.  I can still go to my old shop any time I want and use their stuff that I don't own, so I will whenever I need to do more complex stuff.  But not everyone has that luxury (or experience).

With all that being said, I'd still recommend building a frame up from scratch and taking the time to get exactly what you want.  Just go read my build up of my Scott that I posted last week and you can see how you can get exactly what you want within your budget and have a blast doing it!

Why not just buy a complete bike and take it apart and rebuild it? I mean, if really all you are concerned about is learning how to do it...why does it matter if it is a complete bike or built from seperately purchased parts?

There is almost no reaon to buy a bike in peices unless you are REALLY concerned about having specific parts. Its definitely NOT a money saving method, unless you are religously watching ebay and craigslist for used parts.

I don't necessarily think it's a BAD idea, but I'm in a unique situation that may or may not apply to you:

*I already have at least two working bikes, so if one is out of commission for transferring parts, I can still ride.
* When my hands are in bike grease, I'm in my happy place.
* I've already accumulated all the needed tools over years and years of wrenching (from before indexed shifting was even in existence).

I have saved money building my own, but it was never an all-new build (either much of it was parts I already had, or I bought used or NOS items).