Hi, I have a mid-2012 MBA 11" with i7 processor, 8gb RAM and 256 hard drive (and apple care). I am planning on buying my son a Surface Pro 3 for school (he needs the pen) and they currently have a trade-in promotion for MBA's - up to $650 to be applied to Surface purchase. If the trade-in is decent, I plan to trade in my MBA and then buy the 2014 MBA (for battery life - 2.5 hours battery life is much too short for my needs). My MBA is in great shape, but I don't know what it's worth and would like to have that info before I go to the Microsoft Store (and then head across the mall to the apple store). Thanks for the help!