As I've observed in the past, the proverbs that seemed to 'control' a lot of out parents' and grandparents'; lives often came in contradictory pairs. In this case ...Ok , agreed, sometimes cost and value are not the same thing. ... Our generation(s) were brought up on "save a shilling" our parents and grandparents even more so.
"Look after the pennies and the pounds will look after themselves"
OR
"Pound-wise, penny-foolish"
Kind Regards, John