Well, there are idiots all over the place who will pay a lot more but you can buy brand new GTS take-off rims for $75 US each from Tirerack. With tires I wouldn't pay more than $450 but I'd imagine you can find some idiot on Ebay who will go $600 or higher. My opinion, keep the wheels for the snow tires, they make fine winter wheels.
You have to call TireRack they don't put the take-offs online. They won't always have them in stock but usually do. They have take-offs from most cars that you can pick up really cheap, they make great wheels to mount snow tires on. I got a set of 16" GTS take-offs brand new for $300, no center caps but since I just swap the caps off my summer wheels it didn't matter to me. Michelin Arctic Alpins mounted balanced and delivered total price was under $700. Give them a call and see what they have in stock.