The license system works under the single computer license. This means that one license is valid for one computer. At the beginning, you are allowed to request a free demo license, which is fully functional for 10 days. After that, you need to buy an official full license so that you can commercially use the work acquired from the tool.
If you want to order more than 2 licenses, you will get a discount from the 2nd license on.
There are two alternative license models with different pricing, which you can find here.