I notice a lot of posts from people asking what to buy on a serious budget. Most seem to want to buy new. I'm a big fan of buying used when I can - you can get great deals, and I think it's more environmentally conscious (that's my opinion, but that's another argument for another day). So for example here is my bike; it is a combination of bike parts from over the years. Maybe it'll give you some suggestions on where to find deals.
I can't remember all the prices, so it's hard to say the total price. The point is that there are deals out there.
2001 Cove stiffee in mint shape w/xy seatpost, bb, headset, front derailleur $275 off eBay 2003 Vanilla 125 fork from Pinkbike for under $300 bought a few years ago. Race Face Next LP cranks w/rings - bought a few years ago $130 off Bow Cycle classifieds Candy pedals - brand new, bought from Pinkbike few years ago $70 i think Mavic 519/XT wheels off Pinkbike a few years ago for under $100 Diabolous handlebar, evo grips, seat came off a complete used bike I bought One LX and one Deore shifter were from an old bike; 6 years old and still going strong. Avid BB7 brakes bought for $60 online. Stem, tires, and things like chain and cassette were all bought new at one time.
I've got some good parts on there, although some aren't exactly new, but that doesn't really matter. I prefer to buy and build part by part, but one can do even better when buying a complete bike from the classifeds; you just have to be careful, as nothing will be perfect - it's definately good to be able to see the bike in person first.
I love the suggestion of buying used. I don't know why more people don't consider it.
Another thing you can do is get a part time job at a bike shop. Bike shops of all sizes can always use a part time employee for the weekends. Plus you can learn a lot at the same time.
Or it's always good if you have friends who are part-whores so you can buy their barely used stuff when they want to get the latest and greatest new parts! (You know who you are...CP!)
Everybody loves new stuff, don't they? I am reusing my frame, and a few of the parts. But, I hate to throw stuff out, too. My 1995 Marin Team, used for pre-season road rides and city cruising, will be the recipient of the remainder.