Am agreeing with you, as a shop can only really sell for market value, and by the pure nature of a 'trade in' they buy below market value based on where they see the market value. That way, when they sell on at market value they are still able to make a commercial profit. Therefore given the 33% to 50% mark up retailers need to achieve on the sale of a second hand item, a £200 'Trade-in' price conservatively equates to a £300 market value price ...