How do I sell an item?

Tap the item, then tap the sell chip that appears at the bottom of the screen (it shows the price). Tier-5 and higher items need a press-and-hold on the chip — a small safeguard for valuable items. Selling pays coins only; orders always pay about three times more, so sell only what you truly don't need. Some items can't be sold — generators, Toppers, Keys, and story items. If the sell chip doesn't appear, the item is needed.