Because the show hasn't ended yet, the Iron Throne is not the one you see on screen--that one is still very much occupied, and perhaps its occupant will change (of course, it'll be ten more months till then *tears out hair*). But nevertheless, the HBO Store is offering a replica of it for $30,000.
Strange to think of someone spending so much money on a replica of the iron throne, but then again, there have to be some eccentric billionaires out there looking for a new dining chair. Or, just an extremely devoted fan.
Source: The Wrap