Parent's "a few cents" and what I pay in SoCal for a can of beans ($1.40 regular price; $0.99 on sale) indicate a different scope.

You project a 1:3 ratio. Cheaper estimates of chip cost, more expensive beans suggest the other end of that ratio is $0.03:1.40 indicate the chip cost around 2%, which could potentially be recouped by better inventory practices.