Yes, you can try Office 365 Plus completely for free for 30 days.
The free period starts, when you create the first user. You create a user in the One.com control panel.
During the trial period, you can create 5 users for free. It is possible to add more than 5 users, but you will be billed for the additional users.
No strings attached
When the free period ends, your accounts will be deactivated, unless you have added a credit card. We will send you an email to remind you about this.