I'm not sure all retailers pay the same amount for the product. The more you buy, the better price you usually get. Walmart/Sams Club is a powerhouse and sets many of their own purchase prices, specifications and lead-times. Many of those who want to sell to Walmart agree to those terms or take their product elsewhere. Now Sony may set the MAP (minimum advertised price), but that doesn't mean Walmart doesn't buy the PS3 for less than Target. Because of MAP many places now offer gift cards or freebies so customers are encouraged to buy from them rather than the competition. We have been seeing this on games from Toys-R-Us, Circuit City and Best Buy. Its just a way for them to sell the product for less, without breaking the MAP agreement. Walmart may have needed to move a lot of PS3 product to keep their low purchase pricing. Or it may have been an agreement with Sony to move a lot of product fast for one reason or another.
Also if Walmart gives you a $100 gift card and you use the whole thing, they are not out $100 because they didn't actually pay $100 for the product they sold you. I would be interested to see if they lost anything and if so how much.
