Where can I sell my formal dresses?
Honestly you can sell them at any of these places mentioned above to for the most bang for your buck I'd wait until Halloween and sell them on Ebay as costumes...you'll get considerably more for them :)
You can talk to any of the shops selling dresses in your locality and see if they are interested in buying your dresses for resale. Alternatively, you can open an online shop and take it from there.
Ebay,thrift shop, or places like playtos closet
Check out the phone app Poshmark.
Resale shops. But... I think those are donations. So try some high school girls who are looking for prom dresses.
www.honeybuy.com is very good