Please contact sales directly for a volume discount of more than 5 licenses.
The license is per machine, tied to a MAC address. It is perpetual for the version you purchase. We do not charge yearly maintenance fee. You may get all the updates and bug fixes that we make public for the version for free. For example, if you purchase 3.x.y, you get free updates for 3.x.y, but not 4.a.b and newer versions.
Please note that if an add-on package you purchase depends on other packages, you will need to purchase also the licenses for all dependencies for the add-on package to work. For instance, you will need the BASIC and OPTIMIZATION packages for the STATS package to work properly.