My guess is that they have a system that when an item is purchased another one is ordered. When there is enough for a full case, the case is sent to the store. I’ve worked for a few retailers, and they both did it that way. If the PSP2 is out of stock for awhile, Sears might be having problems getting it from their supplier. Also, the system has glitches sometimes. If there is theft, the system doesn’t know to reorder it.
You can purchase it online and use your giftcard.