The key to that is, not making a big deal about it. People are free to spend their money in whatever way they choose. It doesn't ruin or effect anything in my opinion, but it will if you let it and turn it in to a problem.
But I digress, as I've said before people are allowed to spend their money in whatever way they want to. Whether it's justifiable to you or you disagree with it is irrelevant. People will do what they want, it's their right. If they want to make money off quitting and they have people willing to pay for items, why is that any of our business?