AmEx Blue is a credit card that they offer. One of the benefits is the Best Value Guarentee Program. It's awesome and it really does work.
That program and some others.
Return Protection lets you return a covered item purchased with the Card [ even if you purchased it online ] when the merchant won't take it back. Just contact us within 90 days of the purchase, and you will be credited for the full purchase price, up to $300 per covered item.2
Best Value Guarantee
With the Best Value Guarantee, you'll pay the lowest price available on items purchased with the Card. If you see a covered item advertised in print for less than you paid within 60 days of the purchase date, we'll refund the difference to you, up to $250 per item.3
The Buyer's Assurance Plan extends the terms of the original manufacturer's warranty on a covered product purchased entirely with the Card up to one additional year on U.S. warranties of five years or less.4
No, I don't work for AmEx. Just very happy with the card, as with MANY others.