I'm not sure if this is the right forum to post this question in, but I'm thinking about selling my MB Air and upgrading to a new MB Pro. I have a 2.13 GHz Intel Core 2 Duo Air with 4GB memory and 256GB SSD. It is the mid-2011 "ultimate" version. I'm trying to get a good idea of what I could expect to sell it for, and if there are any sites other than eBay that you recommend selling on. Thanks!