...my local Wally's currently sells the Mobil 1 15w50 in a 5 qt. jug for $26.95 with another qt. for about $8. I don't like walking from one end of the store to get to the auto section so the curbside pickup is great while it's still at no additional charge.
I think that's a pretty good price for the 5 quart 15W50! I think I have the next 2-3 oil changes in stock (along with panic buying of a lifetime of spark plugs!). When my car came out of restoration some 23 years ago, nobody was talking about ZDDP and zinc/phosphorus levels. My old school thoughts were simply older, import and "performance engines" used heavier weight oil, particularly in the summer. 10W-40 was for domestics, we always used Castrol 20W-50 in the imports. Little did I know just how high revving the Pagoda engines are, but I started with a -50 Mobil 1 from the start. It was only when the zinc and phosphorus issues came to everyone's attention did I start reading the details on the Mobil 1 spec sheets, and choosing the one with an educated eye.
So the oil YOU use, Dave, is the same oil I use, and is the Mobil1 full synthetic with the high levels of zinc and phosphorus specified for our cars. Some others come close. Of course it is just one of many suitable oils, and I think most of the top manufacturers have something that works.
PS. That's one crazy Toyota dealer "suggesting" to the MIL that every 90 days she needs the oil changed...