PaintTool SAI is software . It is a commercial product developed by Systemax Software . However, it does offer a way to try the program before committing to a purchase. The Free Trial: 31 Days of Full Access
During these 31 days, you have access to every feature, including all brushes and layering tools. is sai paint tool free
As of now:
No, is not free , though it does offer a limited free trial. Cost & Trial Period PaintTool SAI is software