You can buy 510 grams of peanut butter for only $501.
Of course, this is special peanut butter. It must be kept at -20°C. And it is not intended for human consumption.
This is peanut butter from the National Institute of Standards and Technology intended for use by food analysis laboratories to calibrate their equipment. For example, standard peanut butter consists of 10.4% ± 0.2% saturated fat.
(Link courtesy of Slate.)