You can go to Ebay. There are a lot of great resource pages on Ebay instructing on how to sell your items. Click on the "Sell" tab on their home site to be directed to the "How to Sell" menu. You can also visit consignment stores that will sell your bag for a nominal fee.
-Please note that is against the rules to sell/buy on tPF! Doing so can lead to banishment. You can learn more here:
annie, no offense meant by it. a lot of new users do come on and either don't know that we can't sell here (except on marketplaza) or do know and are quite sneaky about it ("Ooh, I want to sell this thing for this much money here are lots of pics, what do you all think").
On the eBay subforum you can get lots of tips on what to do to avoid scammers and help your item sell for the highest possible amt. My best recommendation is to take lots of good quality pics and thorough document any features that can be used for authentication purposes.