I had a similar problem with an item winding up in my cart for more than it was listed, but I didn't catch it until after my order processed.
I might give Sears a little credit for this one, depending on how it turns out. I used the chat function online and the agent told me that he would put in a request to honor the price and I would be automatically refunded the difference to my card within 3-5 days of the item being picked up.
Here's the iffy part, I used the function at the end of the chat to request a transcript of the conversation to be e-mailed to me, but it showed up with all the numbers in the entire transcript showing only as *****, so the chat is actually useless to show what I should be charged, refunded etc. So lesson learned here, if you go this route use print screen to save your chat before you exit!!
Edit: Just got an e-mail from customer service saying they can't process the price change at this time because the item is scheduled for pickup and that I will have to make the request again after I've picked it up.