Found this on Best Buy's website tonight and I would presume that the price in store would be the same. Been watching Best Buy/Amazon for a sale on the 55" P Series and saw that the S Series is on sale. "Normally" $450 with occasional sales at $400 at Best Buy (Target prices it this way as well) while it's normal price at Walmart is $400. FYI, Walmart's variant (55S401) is on clearance in store only for $348. I'm not sure if there is any real difference in the two or if it's just an anti-price matching ploy. Clearly, Walmart is the better deal, but figured I'd post this for those unable to get the clearance deal/have Best Buy gift cards or rewards/want the Best Buy points/hate to shop at Walmart or whatever other reasons. rtings.com and CNet really like this TV for the value while CR hates it. Good hunting!
EDIT: Amazon is out of stock, but I'll leave this info below for reference.
As jesudas posts in the following thread, Amazon has pm'ed this price on their model: