Guess I'm outta the loop, or have been fine with my rigs. I didn't know the II-Pro was discontinued.
I always liked that amp, IMO a tone giant-Emphasis on "giant" considering what SMPS etc have done since the II PRO was intro'd.
IIRC, these were in the 2K range brand new. I couldn't find a NOS on E-Bay, so I don't know what current market may be.
Of course you have to consider that GC buys their new gear at a considerably lower price point than they sell if for.
If the II PRO still was in production, they would probably pay about $1200 for it new in box; maybe less.
Used, value of everything goes down except the rare and vintage, etc.
Of course they tried to low-ball you, they know you want/need to sell, and as great as it is, that amp is a niche item.
Not every player needs or wants it and it is bulky!
When I moved not too long back, I tendered several basses for them to buy. They sent me back a spreadsheet showing what they would sell the gear in-store for, and offered me that - 30%.
Fair enough- I would have only been able to hope to sell for more to a private party. This way-Done.
Good luck with selling or keeping the II-Pro. Sooner or late, someone may grab it up from you at a better price.