Upgrades have just two basic values to me, the buyer's value and the sellers value. I'd figure there's a nice price advantage to buying upgrades in the secondary market. There's nothing at all wrong with walking away and not looking back. On an upgraded user gun, I'd be willing to pay more for the right combination of upgrades than I figured I could get out of it on resale. Those same upgrades might never have the same value to me if I were paying full retail.