A man who runs a small business has found a way to keep his customers’ shipping costs down: Including a small BAG OF ROCKS. There’s apparently an oddity in USPS’s shipping rate calculation, making it more expensive to ship things that are LESS heavy than other things. In this guy’s case, something that weighs 13.1 ounces costs $7.60 to ship to Colorado from where he is. and that same package weighs 2 pounds, 3 ounces, and costs $5.97 to ship. He added a bag of rocks to make the package heavier, and the shipping price dropped to $5.97.