Microsoft’s new US promotion lets you trade in your old Surface by March 8th to get credit towards a Surface Pro 3. You need to have a fully working device to get as much as $650– the amount depends on the device you intend to trade in. If you’re aiming to hit the $650 mark, that means you should have a 256GB, Core i5-equipped Surface Pro 3 in possession to trade in. So, if you have an old Surface device packing up dust see the full list of potential trade in values for all working devices below. See the source link below for full instructions on how to trade in your Surface device.