Here's a link I picked up from an MB site for a $10 discount on 5 qts of Mobil 1 at Walmart, or other retailer, I assume. The poster on that site had used it and got two 5 qt jugs for $22 at his local Walmart. Check it out if you like this oil.
One person has indicated this wasn't honored at his Walmart. I found another option - only at Autozone, so 'played', and received a $5 discount for 5 qts. Here's that link:
Mobil 1 Scratch & Save game