Sears' Price Match Policy explicitly requires that in order for a price to be considered for the Price Match, it must be a price found, "at another local retail store" or "from a local retail store's online site". Note that in the latter case, they'll compare their sticker price to the online site's price plus shipping, handling and delivery. So the question will really come down to whether
Best Buy is "local" to the Sears store. You say you "live a bit away" from the mall -- does that mean that you don't want to buy at Best Buy because it is too far away? If so, then Price Match might not work for you. (Personally, I'd rather buy from Best Buy than Sears, so just buy from Best Buy and you can be sure they'll match the price. Also, please keep in mind that there are exclusions. Read the policy very carefully so you're not disappointed.)