I am a huge costume junkie and Burning Man habitue, so I speak from experience when I say this is the BEST COSTUME STORE in Vegas! Huge, giant selection of well-organized (by theme) costumes...plus decent shoe selection, too! Plenty of kids costumes as well. Lots of stage makeup and wigs, plus a whole annex of Halloween gore decos in the back. The costumes can be expensive (as with all Halloween stores), but the shoes are surprisingly well-priced, and the wigs and hats (HUGE selection of hats) are really comparatively cheap! And they usually have a decent-sized clearance rack where you can pick up some real bargains :-) I whole-heartedly recommend this store! Friendly, helpful staff, too!
**Note: it's called HALLOWEEN MART on the sign... it's right on Decatur, just south of Russell.