There are supersized containers of laundry detergent (1.64 gallons) that give you the best price per ounce but are heavy and bulky to use. (My father actually asked me how to get the detergent out - you have to press on a rubbery red knob while holding it on its side.)
I don't like these and have been thinking of going to a conventional size. Are there other examples where you debate frugal vs easy?