I learned a tasty little morsel I thought I'd pass along. You've likely heard about the USPS flat rate boxes. You buy the box and it ships by Priority Mail anywhere in the US regardless of the weight. The slogan is "If it fits, it ships". Sounds great. I was waiting for something like this so I can have a more economical method of shipping bricks to random people.
Today I learned that the USPS flat rate boxes aren't all they're cracked up to be. I sold an item on eBay and needed to ship to sunny California. I found a box in the storage room and packed the item. The box was approximately the same size as the medium flat rate box. I figured I'd find out how much it would be to ship using my box and if the flat rate box was cheaper I'd repack the item.
Lo and behold, my packaging shipped for less than half the flat rate cost. Granted, the item only weighed about a pound, but it was sure nice to see that for lighter items you're better off just boxing it yourself than to buy into the flat rate program.