Is signing up for Skype for Business a subscription?

Question

Skype

I was looking for the Skype API, on the way I entered the account and agreed with https://ucwa.skype.com/terms/eula (do not read the rules, then click :)
Then I saw that it is paid, so the question is, agreement with these terms does not imply a paid subscription to this service, or is it activated separately?
ps I don't want to discover the debt later.