PixPlant is available in a fully-featured demo version that will allow you to evaluate the product for 30 days. The demo includes all the functionality but places a watermark on the generated images.
The alternative Zip File links above include the same installer but packed inside a Zip archive.
For Windows run the installer which will setup PixPlant in your computer. On OS X install in the usual way by dragging into the Applications folder.
Latest PixPlant version is 2.1.68 for Windows and 2.1.68 for Mac - the release history is available here.
PixPlant can be purchased at a special price with education and quantity discounts - please visit the Purchase PixPlant section for more details.