An old man wanted to leave his fortune to one of his three sons, so he came up with a task to see who could solve it the best. He gave each of them a small amount of money to buy something that would be able to fill their living room.

The first son bought straw but it was not enough to fill his living room. The next son bought sticks but he was also unable to fill the room. The third son purchased two small items and was able to easily fill the room.

What did he buy?