Thanks for posting this. I have done this rebate for the past several years.
The deal is actually $17 off if you purchase oil + any Mobil 1 Extended Performance Oil Filter or Mobil 1 Motorcycle Oil Filter.
I always purchase both the oil and filter.
Apparently there is a walmart promo code for 15% off online orders: HELLO15
I haven't tried it myself, but SD says it works.
Since walmart doesn't include a receipt with orders shipped to home, I think you'll need to do in-store pickup, and then make sure to request a copy of the pickup receipt showing the price paid.
Unfortunately walmart doesn't sell one of the filters I need. If you're in the same boat, there is promo at AutoZone:
$35.99 OCS 5Qts or 5Qt Jug of Mobil 1 Extended Performance Motor Oil & a Mobil 1 Oil Filter up to $14.99 or a filter greater than $14.99 the oil change special will be $35.99 plus the difference between the filter price and $14.99
Expiration: March 05, 2018
So assuming the regular cost of your filter is $14.99 or less, the price after rebate will be $35.99 - $17 rebate = $17.99 for both oil and filter. Last year there was an additional mail-in rebate from autozone for $5. I don't see a current rebate this time.
All you need to do to get this deal is pick the items up in store - no coupon needed. Online orders do not need a coupon either - you will see the discount in your cart. Here's a screenshot of my cart: