Moose,
Sorry, just saw the thread.
I have about 6 or 7 uniforms, most of which came from militaria shows. You can sometimes find things at thrift stores, militaria stores and antique stores, or even out of the paper, but you will pay a premium price for them. (E-bay may be a good option, but I haven't bought or shopped for military clothing on it yet, some of my friends have sold WWII stuff on it and made good money... You also can't try it on first.)
The best way to get stuff is at a militaria show. Many major cities have them every few months (I think). It will take a bit of research on your part to find one, and you may have to drive a ways to get to it, but you will not be disappointed! Expect to find a great selection and fair prices, and occasionally great prices. I once bought a matching set on one hanger in great shape of wool enlisted: pants, blouse (jacket) with all brass and an overcoat for $40. It was a perfect fit for me.
A typical soldier in WWII was shorter and smaller than most men are now. There is typically an abundance of uniforms for smaller men. If you are well over 6' or have a bulky build, expect a difficult search for your size. Get there early and be prepared to buy as soon as you find something decent that fits. I'm not a big guy, but I have a big fat head (7 and 1/2 " hat). I must have tried on a hundred officer's crusher hats at several shows over a few years before I found one that fit, even then I had to stretch it.
Folks at these things are very friendly, knowledgeable and trusting, don't hesitate to ask strangers or venders for advice. It's important to know what goes with what, don't just buy everything that you like or that fits (unless your loaded) and expect it to look right (to those who know).
Typical prices: depending on condition and rarity
Blouse (wool jacket): $25 - $75
Pants: $10 - $20 They can be tough to find! Shop for a substitute in a thrift store: vertical slit side pockets, no pleats. In Colorado the HWY Patrol used pants that were the spitting image of WWII Air Corps - many of us bought them at the cop shop.
Long Overcoat: $25 - $50 (not needed though)
Garrison cap: $2 - $6
Crusher cap: $50 - $100
Tie: $2 - $10
Shirt: $5 - $20
Brass, patches and wings: Varies immensely $2 - $100 each (Repos are a great way to go to save lots of $.
Belt: $2 - $8 or get a modern Marine belt, they're pretty much the same
Shoes: Don't even hope to find authentic ones. Go to a department store and buy simple lace-up tobacco brown leather shoes. The more plain, the better.
Good luck!
eskimo
