Overcharges on shipping is one of my major complaints. It's kept me from bidding on MANY an auction.
Problem is there is almost always some nut out there who will eat the shipping cost to get the item.
I know I can get a CASE of figures (carded and mint) shipped to me for $7. So why just one LOOSE figure for $5 shipping from some sellers? Oh, some try and sweeten the deal by combining shipping so you don't feel the sting of the first one so much, if you're bidding on multiple items. But what happens if you only end up winning ONE of those auctions. You sure as hell feel the sting then.
IIRC, there is a distinct policy against overcharging for shipping. I think buyers can report that to eBay. Also, IIRC, eBay doesn't make money on the shipping fees, so it's in their best interest as well to go after sellers who maintain that practice of overcharging for shipping.