I don't know the dealers reputation or any possible history between but you might consider talking to him about it, tell him that he is WAY off with his price, tell him it costs $7.95 at CT and inform him that if he would like to sell the ammo you would be willing to pay $9.95 for the ammo (you have already told him you can get it for cheaper) but would like to support his business as long as he can stay somewhat competitive. He certainly isn't making any money off them if they stay on the shelf, and hopefully he is a reasonable person.
OR
Find a new gun shop. I was at one the other day and they wanted $69.95 for a Brick of CCI stingers. That is CRAZY!! Luckily I saw this place on the way to the regular gun shop, where I got my stingers for $44.95 (I think Lebaron lists them for $33 ish). Ya it is over $10, but they are a limited use kinda thing, if I chewed through them like candy then I would try to work something out with them, kinda a mini-volume discount. Try to find a shop that is willing to work with you, because you both need each other. I have given up on this dealer and will not go back. this is not the first time this has happened. They figure a box of Rem. Core Lokt in 30/06 is worth $31.95. While everywhere else is $19.95 to 21.95. How many chances do we give them?