My 4 year old loves to check out all the costumes. Cheap fun. The staff is super nice and don't mind her trying things on. We usually don't buy much. Maybe just some little cheap necklaces or bouncy balls. I have gotten a couple birthday gifts there. Good source for little kids' party favors. Also I think I am going to have to go get that Jessie hat from toy story 2 as my kid loves that movie. Maybe I'll save it for christmas.
Prices on Halloween costumes and such are about the same as they are everywhere but the service is way better than target or wherever. The staff will help you find pieces to match or accessories without pushing them on you.
Also there are plenty of mirrors strategically placed around the store to check yourself out.
Also they have there own parking lot in back so the don't have to pay the meter.