$450-$500 I'd say is a good deal IF its straight.
Ignore the sons poker face. He doesn't want the machine so you could try the walk away game. if he doesn't take 500 or even pushing 550 at absolute max that he can accept as a final offer.. I'd want an extra thrown in too for that
Tell him no one will pay 1000. You can buy a brand new one that's accurate with digital readouts, precise and hasn't been sitting around in a shed for years with stuff stacked on top of it.
You still need to buy new laps, oils, diamond powders..
Does it come with all tools, meaning many dop sticks, there should be some which have a "V", some with a inverted cone, and some flat. Most importanlty a strange angled one which is the 45 dop stick for cutting the table.
There may be rollers for rolling diamond powder into the copper laps. Are there laps? There should be alloy, copper, plastic, diamond?
Does it come with the tool to swap from one dop stick to the other? This would look like a little clamp type device seperate from the machine. You use Iit to transfer the rock from one dop to another accurately.
These are all things you need to check, but most importantly, why he needs to meet your price. You can say you have to buy at least 300 bux worth of extras just to get started if the gear is not there.
Hope you read this before leaving.
I just went up and read your first post.. you may have some or all what you need there. But he doesn't know the names of the items or what they are still , so you can say whatever you want now you have the info
If you want to play, start low