Daz, its hard to say.
Replacement cost is apx $6600 for a new ACDC Pro with shaker, delivery, etc, then u have a costly coinmech on top for some.
The last few sales of the ACDC Pro have been around the $4,000 to $4500 mark and they were sited machines, which tend to be worth a
little less than Home Use Only. Maybe add $300 to $500 extra for home use only ?
The issue with ACDC is that there are also a lot of them out there, which means coming by one 2nd hand is a lot easier than other titles which less numbers were produced. I will never sell my ACDC so it doesn't mater to me whether they are worth 4 grand or 5 grand 2nd hand etc, but they are all worth what someone is willing to pay at the time.
Perhaps when production of ACDC finally stops, and they aren't so easy to come by, then the prices will climb back up somewhat like a lot of other modern Sterns....