The shareware is an international mode of diffusion not limited by the traditionnal circuits of distribution software. 

The sofware suggested is under free test enabling you to fully install and test them in all functions for given length of the software.  

After this period, the software is blocked and propose you either in to buy the licence or to remove the software of your computer.

 A software is not free, its design in general required many months of work, the author expects by diffusing his software a right payment for carried out work.