Been a lurker for a long time (since $1 GC clearance day from AZ) , time to give back:
Mobil 1 has a sweepstakes here
However, if you purchased 5qt M1 from Walmart, upload your receipt then they will send you $10 Walmart Select Certificate. It is basically a $10 off the next 5qt purchase. I just got mine a few days ago. Expiration date is 12/31/18.
If they have a new rebate next quarter then you will get your 5qt almost for free after coupon and rebate (if combinable.)