I managed to find a couple in my price range, as low as $-0.80 each (free with a rebate of 80 cents) - once you've messed with it a few times, there appear to b

I managed to find a couple in my price range, as low as $-0.80 each (free with a rebate of 80 cents) - once you've messed with it a few times, there appear to be some bugs with the math as you might of noticed.