why pay for something when you can get it for free? he has other uses for his pills and i think it was the last three treasures that he got completely free.
why did he take the stone ?
he is at the arcane realm with one with the saber ?
and it was truly OBVIOUS when the auctioneer said "we have three big artifacts" that MC will get all three of them with his, oh obvious again, three "for free" tickets