to the right person i think 100-125...but you have to find that right buyer
i have bought rough but working xs2300's for as low as 30.
the other thing to consider is opportunity cost. rsd250's are going for under 100, so if the buyer isnt a collector, and just wants a amp for an install it doesnt make alot of sense to buy a older amp for more money.
my ex-girlfriend said "its car audio or me"
i've had tougher choices at a soda machine...
The link was to inform you that someone is asking $110 for one. A place to start in a sense, not for YOU to buy one.
IMHO, I'd look to get about $80 shipped, not $80 + shipping, but $80 shipped. I've seen'em sell for, as Brian stated, about $40-$60 on ebay in a 8+/10.
"ZPA's will have the same sound essentially as you get from the MS, they just feature a bigger shinier set of balls."