Where can I get inexpensive dance costumes?

I am a dance instructor for the Cleveland YMCAs and am looking for the most inexpensive costuming I can find. I am charging my clients only $10.00 and they have all the same leotards. So its just the matter of a skirt, tutu or shorts and maybe an accessory for the hair or a belt. Any suggestions would be helpful. I looked on ebay and did find tutus for a reasonable price. but am looking for other ideas as well. Thanks :)