Initially I wanted all of my stock to be free. I still do. But it kept getting stolen by shady characters and businesses who were using my face for profit / advertisement that I had never signed up for. I was on a billboard in Egypt! So I changed my stocks to paid content, but I charge teh bare minimum price. The way anyone who is a regular user of DA can beg/borrow 10 points from friends or random users.
In the end, I make enough hobby money from selling my stocks for 10 cents for it to be worth it. They're unlimited content, so it adds up over time. It's nothing to live off of, but it's a decent perk.
(Also, I don't support people doing commissions for 10 points. Custom arts needs to charge at the very least minimum wage. My stuff is different because, as I said, it's unlimited)