If its not a decision on eat or buy cheap oil, buy an oil that you can rest easy running. I'm as cheap as they come for all my 50 years. Still have my 3rd grade lunch money under my pillow but I will not chance $10K in engine problem to find out if I got a good deal on cheap oil. I can envision something weird like foaming, clotting when mixed with gas blowby or moisture, separation while sitting, etc. Or over detergent/solvent and break loose large clumps of varnish/sludge and clog a passage.
You're talking 5 qts for $15 of ??? oil vs $17 for QS syn blend or SuperTech full Syn and rest easy. Is $2 two or three times a year worth the hassle of a mystery oil that MIGHT be Ok?