200.00 is not bad if you're assuming that it is an easy fix, which you should never do. When haggling a price, you always assume (especially in front of the seller) that you'll have to buy a new board and monitor. And, in that event you should ask him, in light of it being "DEAD" if he'll take 150.00.
If you detect he isn't that familiar with these games....say something like, "Yeah, these things are soo old now, it's common that the circuitry gets fried and your left with a box." That'll make him think that you're doing him a favor by taking it off his hands, that he's lucky he's getting anything at all for it.