If one lives in an area with 6% sales tax, the tax on one $0.40 item will be two cents, but the tax on two such items would be five cents. So purchasing the items together costs a penny more than buying them separately.

My idea for a hopelessly impractical method of saving pennies, therefore, would be a machine into which you would input the prices of items you wanted to buy; it would then inform you of the best way to group those items in separate transactions so as to minimize the amount of sales tax paid.

Functionally, the device would work by computing the 'residual' sales tax on each item (the fractional portion after rounding) and try to assign items into groups so that the residual for each group was as close to $0.0049 as possible without going over.

As to whether the extra effort would be worth the five or ten cents one might save on a shopping trip, well, this is the halfbakery...
-- supercat, Jan 26 2005

I don't think this would actualy be THAT difficult to program and place on one of the graphic calculators or on a pda... [+]
-- photojunkie, Jan 27 2005


I'll wager your penny and your taxes are both kept by the store when you return one item of two or more.
-- reensure, Jan 27 2005


Actually, my experience is that sales taxes are rounded when products are returned. So buying two $0.27 items in one transaction ($0.03 tax total) and returning them separately ($0.02 tax each) would net a $0.01 gain. But I don't favor buying and returning items for no good reason; that idea would have to go under public:evil.

BTW, no not Michigan. I actually live where most sales taxes are higher, but I thought 6% seemed a nicer number to work with than 7.375% or some other such nonsense.
-- supercat, Jan 28 2005



random, halfbakery