I'm pretty sure the city taxes are higher in Boulder. In general most things are more expensive in Boulder. Broomfield - as far as food is concerned is cheaper because they have Wal-Mart etc... But I would honestly recommend Sunflower Market (now sprouts) on South Boulder Road and HWY 287. Produce is very reasonably priced depending on whats in season, we get everything there. Farm shares are also an option for food. For clothing the Flatirons Mall in Broomfield has more of your basic/expected mall stores. The 28th Street Mall in Boulder and Pearl Street have shops that are less common but may also be more expensive.