When you run the presses full time to print American currency, it tends to be worth less and buy less.
While this is true,it still does not account for the disparity between $150 barrel crude and $2.25 gallon gasoline (more or less) back in the early part of this century and the $107 barrel crude and $4.00 gallon gasoline today. Neither will it account for the difference in fuel prices between high dollar highly regulated west coast prices and areas having less regulation and lower prices.