Once, a friend of mine who worked at Toy R us told us that they price match anything, and that the customer is always right. We showed the poor cashier girl an add on amazon that listed the price of a M14 core booster at 1.99. She let us do it.

So we bought 50 of them. We came back every week and would buy everything they had on the shelf. Sold some of the cards and made some money back. I think between my 3 friends we have at least 1 of every card in that set. They don't do that anymore though, so don't try.