A good set of TK armor isn't cheap, regardless of where it's bought. Those at the 501st put the most $ and best work into their stuff. If you want a good screen-accurate costume, contact the 501st and they can help you out. If you just want a costume to poke around in, you might try a Rubies or somesuch. My Jedi costume I wear for the Rebel Legion has cost me around $800 in total, and I put most of it together myself. It's a matter of how nice you want it to look versus how much you want to spend. There are shortcuts, but it will sacrifice quality to some degree.