But stick to the drawing tutorials and Drawing Desk is excellent.
There are a number of licensed tutorials, including Marvel, with more in-app purchases. Drawing Desk is a also a basic digital art app with the core tools you'd want and a decent simulation of paints and markers, but this isn't its real intent. One thing to note, within Drawing Desk are a number of sub-apps for digital art, and more, and it can be a little confused as to what is free and what needs to be purchased. But stick to the drawing tutorials and Drawing Desk is excellent.