Just make sure you have the original receipt with you. I made a round trip back home to grab a receipt the first time but it was worth it to save a 100$ on a BBQ.
Also they have to have the item in stock. You can also get credited again on the same item if it drops in price again. We bought the Amelia dining table set for 780$, it dropped to 599.97$, I got credited and was happy. Went back 2 days later and saw that the last set was dropped to 328$ so I ran to customer service and after some confirmation on the price got credited another 270$. Was very happy!
Have a nice day!