It varies from item to item, but I have heard about 30%. One thing you should not do is sit and try and argue with the guy to give you a huge discount. One thing alot of people dont realize is that these guys have to make a living too; it's not like the dealers buy something for 20$ and sell it for 200. Snap on apparantly makes thier dealers bend over when they want to start up a route, whereas matco has it alot easier.
One thing that you may want to ask about is what I BELIEVE he called a branch box. Basically, my guy got a big roll cab full of random tools that he bought for WAY below list from the local "warehouse," because another truck went under. Snap on Doesnt warehouse tools so much, but boxes and things like tat, so a Dealer can pick one up and deliver it instead of waiting and paying for truck freight.
Anyway, This is how I got the 130$ ratchet for 40. The one he had was full of random tools. A snap on multi meter, slugging wrenches, wheelnut sized sockets, a few air tools, hammers, like 10 sets of mini-torx, gear pullers etc. Everything was at a big discount. My guy didnt make much money (if any) off of it but it was the sort of thing where he would pass the savings onto his customers to keep them happy with a few good deals.
Jim