You're not doing a buyer any service... any buyer who is not an idiot can determine the shipping charges (inflated or otherwise). Any time you buy something on the Internet, ebay or otherwise, you have to figure how much it will cost to ship versus what you could get it for locally and add that to the price.
All you're doing is opening your self up to being neg'd (which you can't retalliate for since you've already neut'd the guy).