So ran into a little problem but more of an idea, but problem

I draw about a minimum of everyday. During class, on my worksheets, test, ect..

Dad comes by ask what I'm doing, I said doing commissions, but I forgot. You get paid when doing commissions. He thought I got paid for doing that I said I was doing request my bad. 

Few min ago he asked what I was doing. I said doing request. Next thing you know he asked. "Did you charge them" I paused and gave me "Uuuuh crap?" face

He chuckled and said, "You're working for free. You'll see what I mean." Then he started singing down the stairs. 

Now let's pause for a sec. I enjoy doing these, but when I do a request, It takes me a maximum of 4-6 hours to sketch, lineart, base color, shade, and background. That's about $5-10. But like, I don't have any of that paypal stuff and neither do the people who request this stuff. Now don't get me wrong their are people who are my and your age and younger getting paid bucks from an app they made, just by coding stuff.

Now my problem/question is. If I started charging this stuff, how the heck do I even start!?