More commonly done at the wal-mart super centers. You can take an ad from another retailer in and they will price match it. Good to do if another store has sold out of the product while its on sale. Kmart is known for that. I've been held up in line at a wally super center while a woman was price matching all her groceries with ads from meijer and kroger.
Usually not. Although I've seen Walmart prices vary widely from store to store for the same oil. Your best bet is to check and see if there is an aisle close by where they have their clearance items. Sometimes you get a good price on oil there.
Otherwise I will just watch for the Kmart ad and price match the oil. Works every time!
I'm in northern NJ and I've never seen them put Mobil 1 on sale. They will jack the prices up on the 5 quart jugs, which they have a limited selection of, and then shortly afterwards runs a "price roll back" special. Though in all honesty they haven't done that for a while. The quarts are $4.88 for the SS and $5.38 for Mobil 1 EP, very limited selection. Advance Auto a 1/2 mile a way charges about the same price for Mobil 1 SS quarts and has the full selection in stock. Though their price for the new Mobil 1 EP oils is about $5.98, $0.60/quart higher than Walmart's. But they have a better assortment in stock. There's nothing like finding 2 quarts of the oil you want/need at Walmart then having to drive all over and waste expensive gas to get the rest of the oil you need .