Okay, so what's this Mac mini worth?

[Wailer]

I'd lowball and if you don't get it, forget it. Sure, he may be insulted, but if he really needs to sell you could be helping him out. If he doesn't need to sell, he probably won't take a "reasonable" price anyway. You can afford if he says 'no' since there are an essentially unlimited supply of mac minis around.

I've seen so many "must sell tonight" or "just offer me anything" ads that come back a week later at a slightly lower price.

I don't value my time enough when I look on craigslist. I always underestimate the value of new/refurb with warranty, being able to pick it up whenever I want, pay with a credit card, and take it back/send it back if something is really odd.