Yes it's $5 at RockAuto, but I have to pay $4 for shipping.The Amazon filter (PG) for my car is clearly a Microgard. (Made in Vietnam). The same filter can be found on RA for even less. (Vietnam).
I'm still confused as to the STP line at Autozone. I don't think it's a Microgard clone as it's made in China. AFAIK, Microgard filters (And the clones) are all made in Vietnam and nowhere else.