Amazon offers the Mobil 1 0W-40 1-Quart Synthetic Motor Oil 6-Pack, model no. 96989, for $41.97. This $12 mail-in rebate cuts it to $29.97. With free shipping, that's $5.99 per quart and the lowest total price we could find for this quantity by $24. Sales tax is added where applicable. Deal ends May 31.