Pro versions of most stern pros are headed into the mid 5k range used. Some are probably already there and have been sold at around that price.
It's also been said that home versions can be had from distributors that can't sell them at $3500.
Street value IMO is closer to $2500 (maybe a little more, but i'd only pay $2500) used, which is a really good value.
The odd thing is that the normal stern home pin did not have a real coin door, that costco version seems to.
IMO, right now is a bad time to buy any modern stern, there are more pins out there than buyers.