No dance outlets in NYC, but you can find some great deals on the discount racks. Check out Capezio Dance theater at:
1650 BROADWAY at 51ST STREET
NEW YORK NY, 10019
I have gotten leotards there for as little as $10. Stores online have little overhead but you also cannot try things on. You may have to pay a little more but there are usually several racks of discontinued or clearance items for less money there. They also give discounts to certain dance schools. Check to see if yours is on their list.
* There is a place in Flushing (Queens) that is a discount dance wear place. However, I don't believe they have a show room and are just mail order. You can get things from there super fast because they are in the city. Often 2 days or even the next day. http://www.nydancewear.com/home.html