From the above site:
Just a quick note today. I'm happy to let you know that we've just turned on free trials of Azure Active Directory Premium. Now you can get a free 90 day trial of Azure AD Premium for up to 100 users.
And I've got one other bit of cool news to share. As of last weekend, Azure AD is now pre-integrated with 2035 SAAS Applications. The team has been kicking it over the past several month, adding on average 120 new apps a week!
Start to learn!