Overcoming argument "I can haul it to the scrap yard, myself"
Today, I went to several yard sales (got a whole carload of electronics, BTW). Anyway, one place was a self-employed plumber. I asked if he had someone buying his copper pipe. He told me he hauls it to the scrap yard, himself (about 10 miles). Instead of trying to get him to sell to me, I told him "That would be better for you cause I'd only give you about half of what the yard does. I sell to them, too". Then he said "Yeah but you'd come here and pick it up, wouldn't you?" "Oh, sure. You could throw the pipe in a bucket beside the house and just call or email me when you get 30-40 pounds. Leave me a note on it "Mick, take this bucket of copper pipe (or whatever - just something to show the Sheriff when he stops me). (He thought that was pretty funny). You don't even need to be here - I'll put the money in an envelope and leave it inside the screen door". He thought that was a pretty good deal - he could make a whole lot more as a plumber in the half day he'd spend loading the stuff, hauling it in and driving back home.
I didn't convince him or argue - he convinced himself and HE told ME why he'd be better off selling to me.