What are some alternatives?
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
PaintTool SAI - Learn to draw in different ways.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
Clip Studio Paint - Powerful drawing and illustration tool.
MediBang Paint - The official site for MediBang Paint, the free digital painting and manga creation software. You can download the latest version of MediBang Paint here, and get news and tutorials.