Walmart offers the Mobil 1 Advanced 0W-40 Full Synthetic Motor Oil 5-Quart for $22.88. Redeem this $12 mail-in rebate to drop it to $10.88. Opt for in-store pickup to avoid the $5.99 shipping charge. That's $12 under last week's mention and the lowest price we could find by $17.
WD-40 is handy in a lot more situations than you likely realize.