I believe making a profit is actually quite a "grown-up" thing to do. There is no rule against making a profit, even on a mistake purchase.
I am not sure why some on this site are so insecure they have to try to make sure every other seller gets the minimum amount for merchandise. Sell those for $275 bro, since these other guys obviously have no clue about shipping and PayPal fees. And just for everyone's knowledge, selling the skis for $250 he would pay $10 in PayPal fees, plus probably lose a couple of bucks on shipping and end up losing $15.