MathXpert comes in three versions: Algebra Assistant, Precalculus Assistant, and Calculus Assistant.
You will see the prices on the next screen, long before your final choice to purchase or not.
Precalculus Assistant includes Algebra Assistant, and Calculus Assistant includes Precalculus and Algebra.
MathXpert runs on any version of Windows. You can run it on a Mac using Parallels or BootCamp, or on Linux using WINE.
You can download any of the three Assistants, either in a free trial version (with limited functionality), or the full version.
The trial version only allows you to work the 6500 problems that come with MathXpert.
If you want to solve your own problems or those assigned in your class, you must purchase.