Walmart offers the Pennzoil Ultra Platinum OW-20 5-Quart Motor Oil Jug for $22.47. Redeem this $10 mail-in/electronic rebate to cut that to $12.97. Choose in-store pickup to dodge the $5.99 shipping fee. That's $2 under yesterday's mention in another weight and the lowest price we could find in any weight today by $12. It keeps pistons clean and improves fuel economy. Rebate expires December 31.