Just downoad PXL8 for your system, install and run. If you don't enter a license key, you can run a time limited trial and try out all the features for free. The only limitation is that a timer will count down and force you to quit. You can restart as often as you want. If you get want to get rid of the timer, you can buy a license key below!
The current version is beta 0.8.1:
PXL8 requires Java 7 or later. Get the latest version here.