Look at it: https://ubuntu.com/pricing/pro
Whoever did this web design should be shot.
I had to go partway through placing an order to find out this is an annual (as opposed to monthly, quarterly, or lifetime) fee. I still have no idea which fees are per-machine, and which are one-time.
The server pricing is messed up too:
(1) I would never pay $225/year for my nano instances.
(2) I have no idea how to count licenses in my cloud, where servers spin up and down all the time in response to load.
(3) I'd pay a lot more for uber-large instances (if I were currently using them, which I'm currently not).
The server pricing ought to just take a flat cut of my EC2 costs. I'd gladly pay Ubuntu a flat markup.