Religious-order priests, such as Pope Francis, do take a vow of poverty. Anyway, we are all called to practice evangelical poverty, appropriate to our station in life, just as we are called to practice chastity and obedience.
Well I think common sense is the rule here. A priest driving a Mercedes is probably really bad optics. I don’t know any that do or would But they are not required to drive a beater either.
Frankly I don’t want my priest breaking down on the side of the road when I’m in the hospital waiting on last rites. :-)