Indeed, a crazy idea. Considering any decent design would take at least 3 hours of work, you'd be making $5/hour. To make it worthwhile for you, you'd have to

Indeed, a crazy idea. Considering any decent design would take at least 3 hours of work, you'd be making $5/hour. To make it worthwhile for you, you'd have to spend at most 1h per design, in which case it wouldn't be worth the $15 for the client, or a spot on your portfolio.