Could you have bought ianother one at the sale price and return the regular priced one? Even Costco tells me to do it that way
When I do that at Costco, i normally take my first receipt with me, buy another of the item at the sale price, then stop by Customer Service on the way out. I don't feel bad since they can resell the unopened item easily.
One exception was when they marked my color LaserJet printer $50 off. I tried to get the difference and keep my printer, but they said it had been over 30 days since i purchased.
So i had to come home, box everything up, drag the used, opened printer to the return desk, then buy the printer again. So, here's the rub with that transaction: they had 2 printers that, according to HP, were nearly identical with one letter different in the model number. I originally bought the slightly newer model -- both models were the exact same price but different model/item numbers. When I saw the price reduction in the store, I saw only the other model was in stock, so I couldn't re-by it again on sale and return it with the other receipt. The numbers wouldn't match. This is especially annoying when the item has been through some installation process and/or is pretty bulky. Dragging the item back to the store just to replace it with the same one is not always a pleasant experience..
The funny part is, after i brought the used printer in for a refund so I could buy the other one, the same model appeared again on the shelves again! I guess they had more that hadn't been moved to the shelves yet.
The process works great as long as the first purchase and second purchase are the exact same item.