If you bothered to call them and ask
Any charges shown on the website are rounded 'up' on quantity to cover them, i.e if you ordered 5 sticker sets, that is gonna cost bugger all, but if you order 5 DYE 4 day Explorers, it is gonna cost a bomb. Upon ordering Planet will charge you the actual cost of shipping, if it is cheaper than stated at the time of ordering on the interweb that is what you get charged, and they leave it the same if it is more expensive. As you can see, this leaves them open to loosing money on certain orders, but due to the spectrum of kit they sell, they cannot put a shipping cost on every single item.
This is the way it was explained to me, Planet, please dont shoot me if I got it all wrong