Check the official website for a trial version to see if it fits your workflow.
If the price is currently out of reach, consider these safer paths:
Surfaces that react to the amount of water or oil on your brush.
The ability to see your artwork in a "virtual gallery" or on a real-world easel. The Dangers of "Crack Link" Downloads
Tools like Krita are completely free, open-source, and offer incredibly powerful brush engines that rival paid software.