I have but it's rare.
For example, Napa here is very expensive for oil, so most of the time I get PP or Pennzoil Conventional or something like that heavily on sale at WalMart. I bought some oil from Superstore a couple years ago that was like a buck or 2 per quart, was black with a yellow label, seemed to run good in my Saturn at the time. I think it was a SOPUS oil, bottles were identical shape to FormulaShell.