hjm,
I have a 2002 Gun Traders Guide Twenty Fifth Edition. Cost is $23.95
It shows your S&W Model 66, 357 Combat Magnum Stainless as:
6" bbl........NiB $319.00
6" bbl........Ex $255.00
6" bbl........Gd $173.00
As with anything, the value relates heavily as to what a buyer is willing to pay and seller is willing to accept.
Other here that deal in guns and have much more experience in buying and selling them than I, will surely help you!
Edit
OH, and there is an addition of $45.00 for Target Options TH & TT
