Later I told him that it would probably be ok if he gave it to me since I was the one that paid for him to go to club to create the art. He argued that it was their art supplies, and then I reminded him that we pay for him to go there, and thus we pay for the supplies, too.
What a smart kid. I told him that we would start looking more into art and artists and art history. I love that he valued his work so much.