I recommend autodesk sketchbook.It's free and has a variety of brushes,I used it for this painting too.
Lol Hope you earn money soon.It's possible to draw in your phone with your finger tho.I used to do that when I have no stylus.
Yeah, I mean stylus. lol I want to get myself one of those but then I see my wallet, it ain't got nothing in, even for the cheapest one. I need to learn how to earn!
You can do this on a phone? Do you need a pen for this? Don't need to tag me, I'll hang my tab here for now while I read novel. Hehe