I don't know how much Wallmart sells it for. But they sell it in one gallon containers which I like. I fill the empty oil containers with used oil to take down to the recycling center.
That's they only product that makes me go to Wallmart...
Right after I change oils and use Mobil 1 15W-50, I find that the oil pressure gauge runs a little higher. After a few days I don't notice it anymore.
Do you see the same thing?