Well, total value on the new stone is $34,700. My old stone that I am trading is valued/bought close to $17k. So all in all, I am shelling about $18k on top of the trade in.
Searching for comps is pretty easy with things like this using the tool at the top of the page. There are dozens of similar stones offered by the dealers who advertise here and your's is right in the middle of the pack in terms of price. We don't know enough about the tradein to know if the price was right on that end of the deal but if this were a cash deal it's nicely competitive.