Sorry to double post, but I contacted the Sears support. Here is their response to the price change.
"Andy, I have checked and I'm sorry to inform you that the discount has ended and the price of the item is reflecting as the regular price when you add the item to cart.
During the overnight hours Sears.com/Kmart.com performs daily batch jobs which change the pricing on our websites. During this time the pricing changes first on the checkout page, then on the search page, and lastly on the Product Description page. During this time you will see pricing discrepancies between pages. Please,. go all the way to checkout. The price at checkout is the correct price."
I accidentally ordered two
Let me know if you want to sell the extra set you got. Looks like I just got shafted on buying it online due to their website not working right, and then the price changing in the cart before the listed prices got updated.