If you need Halloween, Renaissance fair costumes etc. Head over to A and K costumes.
This company has it all for your costume needs. They can custom make your costume or they also offer rentals of their inventory. If you can think of it they probably carry it. They have clean and spacious dressing rooms and a very friendly staff. They are very helpful if you are struggling with your costume needs. They have a large selection with a wide variety os sizes available. Act quick as they do get busy as Halloween approaches. Rental prices vary according to costume, but are fair.