Sales Incentive #6: trade-in allowances

When selling physical products, consider offering an allowance for returning used or previous versions of the item. This makes special sense when the trade-in can be sold to another buyer, like automobile and camera retailers routinely do.

Train yourself to be creative. In the case of books, especially when dealing with high-margin items where economies of scale reduce per-unit production costs. For example, even if a publisher offered a "trade in" on earlier versions of a book or CD and discarded them, the profits from sales of the new versions could generate healthy profits.