Generally speaking, this is an early makeup of a shoe that's made so designers and retailers can see upcoming models. There are different types, of course. "Looksee" samples are typically in a size 9 and made for the reason above. "Weartest" samples are made in various sizes (basketball samples are most commonly size 13) to see how a new sneaker performs. And "player" samples are just another way of sayong "player exclusives." Samples occasionally turn up on eBay or at company sample sales (or at Portland consignment shops) and are definitely sought after in some circles.