I would highly recommend taking the rod building course through fish tales. I took it a few years back and have built quite a few rods for myself and others since then. Total build time will be ~12-16 hours depending on how complex you want to get (i.e. spinning your own handles, assembly of reel seats, creative thread wraps etc.). I've built rods for as cheap as $100 all in. But you're probably going to be in the $200 range as long as you don't go too crazy with your first one.
Once you get the hang of it you will find that it's quite easy to build your own rod, and a great way to spend the cold winter evenings.
The forum that Don mentioned is a good one, and there are a couple of great books as well.
This is one of the best IMO:
http://www.amazon.ca/Fly-Rod-Building-Made-Easy/dp/0881505110
Happy building!