Amazon has the 5-quart bottle of Pennzoil Platinum Full Synthetic 0W-20 for $21.82 when you subscribe and save. You can cancel at any time. When you buy 2 bottles, you qualify for a $25 rebate, making it just $18.64 for 10 quarts after rebate. Amazon also has 10W-30, 5W-20, 5W-30 for $1-2 more per bottle for a limited time. Limit 2 rebates per household and it ends October 31, 2022.