Walmart offers a selection of Mobil 1 and Mobil Super Motor Oil 5-Quart Bottles in a variety of grades, with prices starting at $14.17. This mail-in rebate drops the starting price to $7.17. (The rebate amount varies based on the type of oil you buy.) Opt for in-store pickup to avoid the $5.99 shipping fee. Check here for eligible products. Deal ends October 31.
Note: Although Walmart is not specified on the rebate, customer service states that this list is not all-inclusive, as it reads "some participating retailers".
Most taxpayers will see their tax bill go down during 2018. That could impact which type of account -- traditional or Roth -- makes sense for you.