You can, it's an actual market. The price is just high, because the chance to get them is low. If you could buy them for what I assume you expect to be a lower

You can, it's an actual market. The price is just high, because the chance to get them is low. If you could buy them for what I assume you expect to be a lower amount, they would not sell nearly as many chests, or no one would want the item anymore because it's no longer rare.