Always the same bottom line.. seller will want as much as possible and try to pish the price a bit... buyer wants to pay less... in the middle is a possible deal.
So he has a "mate" that is after them also?? Why dont he sell to his "mate" straight up then? Mate can have them so long as he pays more than you???
determine your price, knock $300 off and offer.. if he then says "mate has offered X" then he wants to sell to you anyway but just wants to squeeze a few more $$ out of the deal.
When i buy pins i always remember the golden rule... be prepared to walk away and do just that to stand your ground... yeh ive lost a few pins that way, but ive also got my deal more times...
good luck