  Before purchase, a buyer of an experience good learns about the product's fit
using various information sources, including some of which the seller may be
unaware of. The buyer, however, can conclusively learn the fit only after
purchasing and trying out the product. We show that the seller can use a simple
mechanism to best take advantage of the buyer's post-purchase learning to
maximize his guaranteed-profit. We show that this mechanism combines a generous
refund, which performs well when the buyer is relatively informed, with
non-refundable random discounts, which work well when the buyer is relatively
uninformed.
