1 unit = 1 user*month.
In our pricing model, we propose you to choose from a selection of packs of units. A unit is the access of one user during one month to the system. If you purchase a Pack 24 Units and have 4 people using the system every month, you will use your 24 units in 6 months. Then, if you don't change your plan, you will automatically purchase a new Pack 24 Units and start using it the next month.
If, for some reason, 1 user doesn't use the system during 1 month, you will have 1 unit left at the end of the 6 months and the automatic purchase will grant you 24 additional units, making a total of 25 units.
It can really be considered as available minutes on a prepaid phone card; you are charged based on what you use.
A GB*month is the use of 1 GB during 1 month. In the previous example, if the 4 people use 2.7 GB during their first month, 3 GB*month will be removed from the 24 available ones. If you use up all your 24 GB*month before using all your user*month, 5 €/GB*month will be automatically purchased.
It can be considered as a 3G plan on top of your prepaid card that would allow you to surf online up to a certain download quota.