You can get $3-5M per year being decent on both sides of the court (Barnes, Dunleavy, Pondexter, Carroll who's getting a raise this summer).
You can get $6-7M per year being really good on one side of the court and salvageable on the other side (Redick, Korver, Meeks, Tucker, Allen).
You can get $8-12M per year being solid-good on both sides of the court (Ariza, Deng, Iguodala, Parsons would have been here, but the Mavs made him a max player to force the Rockets' hand).
You can get the max or close to it if you can play both sides of the court really well (George, Hayward, Thompson, Butler, Leonard).
Green probably belongs in the $8-12M category, but to get a good player from a championship contending team you're going to have to overpay in this market.