I have done real well finding those diamonds in the rough with electronics. I got an audiocontrol panteges AMP for $100 (5x200) It's good.
Got an Emotiva xpa5 2nd gen for $400
It's a lot of fun when you can nab that great deal I admit that and I do think it's worth it. I have passed on several things I regret as well. And it's funny you still question why you didn't buy it even though what I have is probably better now
But for goodness sakes just offer the guy $150 and lets get on with it