I'm the only person who has one available for sale in shops or trades! I know it's a high-end prize for the recycle beast but have no idea what to value it at....any advice?

the trade you set up sounds like a reasonable offer, though I'm not so sure. Either way, I would guess about 40-60Mil sounds fair. I think I have seen it as low as 35Mil, though that was a looong time ago