What apps am I allowed to use

What apps am I allowed to use

I once opened a free account and lately paid for mail only.
When I open the Zoho site, the menu has a Show your apps entry and when I click on it, it shows a lot of apps. I can open them too.

My question is: am I allowed to use all these apps, and when not, why do I have access to all these apps?

I just wanted all those app and licensing stuff would be as clear as the mail GUI :-(