Not to mention a plastic replica. And it wasn't even like a charity auction. Holy shit, a couple thousand would've felt like a stretch for something like that.
Edit: wait, why does it have "jewel embellishments"? What the fuck on Earth? I never watched the show, but every time I've seen the throne, it's clearly pure iron. I feel like I'm going to have a stroke.
Game of money laundering, or alternatively game of bribery
It appears there were a lot of actual movie set items in this auction lot, in addition to the replica throne... Perhaps some people assumed the throne was the set throne