After the 30-day free trial period of Unraid, you can choose one of the three licenses. There is the “Basic”, the “Plus” and the “Pro” license. The licenses differ in the number of storage devices that can be mounted. With “Basic” there are up to 6, with “Plus” there are up to 12 and with “Pro” there are unlimited hard disks.
The Basic license currently costs $59, the Plus $89 and the Pro $129.