Walmart offers the Mobil 1 Synthetic Motor Oil 5-Quart Jug in 0W-20 Advanced Fuel Economy Full Synthetic for $22.88. (Amazon has it for the same with free shipping for Prime members only.) Opt for in-store pickup to avoid the $4.97 shipping charge. That's tied with our mention from a week ago and the lowest price we could find by $5.
There are many ways for seniors to get cheap -- and even free -- entertainment and services.