Again, you won't find many - if any - stores that specialize in cosplaying. Least none in the US (most likely only in Japan). You can get recommendations to people who make props, wigs and costumes but be warned, you can end up spending HUNDREDS of dollars on something that might not be well made.
Example, for wigs most people go with a certain well known "wig maker". While she does decent work, she's not a true wig maker and uses things like chaulk and glue to make wigs look "authentic". I won't knock her and say she's bad but at the same time, you might end up spending over $200 on a wig that's not well made.
Then you also have to keep in mind that many "commissioners" aren't cheap. A costume that you could probably make for under $100 can cost you several hundred dollars - some even pay nearly $1000 - on a costume. Look for local seamstresses if you want a costume made to your measurements.
As for prop makers. Keep in mind that a good prop maker is going to charge you, again, hundreds of dollars and shipping (depending on what you get) isn't going to be cheap either. I've read about people who spent $500 on a sword that was basically foam board and tin foil! Talk about a rip off.
Watch out for EBay. Especially those on EBay who use images from other sites and are from China. NEVER order anything from someone in China because they typically WILL rip you off. I know several Chinese Ebayers who ripped off well known cosplayers by using those cosplayers images to pass off costumes as their own. So watch out for there.
Again, if you want more help the best place to start is with cosplay.com.