Buying paper is a common part of the cartooning business. The standard letter size, naturally, but I also sometimes buy reams of 11"x17" paper for various purposes. When I do, my cosplayer friends always want a portion for patterning.
I've rarely had sufficiently complicated cosplay to warrant patterning, and it always feels weird to have paper taped all over your body. I can't deny the efficacy of the process, however, as the costumes that grew from that early work were pretty dang awesome.
For the entire run, please visit www.CosPainComic.com!