ANYONE walking on a tool truck knows they're paying a premium, because he's *right there* with what you need *right now*, and it's A+ #1 quality goods.
So if you're gonna snivel that his (damned fine) tools cost so much, then you pay for your discount with inconvenience of going into town.
I'll still walk onto a tool truck when there's something specific I want (and I haven't turned a wrench as my primary living making fun for years), knowing they will charge me for being there when I need it, like right now, and what I get will be of excellent quality, and if it breaks, I can catch the truck next week to make it right.
OK... Scenario Time:
Buyer: (Walks on tool truck) "Hey. I was wondering if you'd sell me a single separate allen drive socket. I need a 4mm x 3/8, Can you do it?
It goes one of 2 ways:
Truck guy: Nah, can't break a set to do it, sorry, bud, but I got a screaming deal on a full set. You interested?
Buyer: (either) That's OK, thanks. (Leaves truck) -or- "Let me see the set, and how much?"
OR...
Truck guy: Yeah, I can do that. $14 bucks, and I'll throw in the tax"
Buyer: (Pulling out wallet) "You want cash, or will you take my plastic?"