Look at the very bottom of the time tracker page. It shows:
This is the intended behavior.
When they first sign up with TMetric, all new users receive a free 30-day trial period allowing them to try all available features of TMetric.
Once this period is over, you have a chance to choose which subscription plan to use.
I thought it was the Deviant Art wordpress template that might have been a trial version. It doesn't even make sense to have a 30 day trial, because there is a free tier which I am using that never expires (that I know of). I've been using tmetric for over a year now, and that message has showed up much more recently than 30 days after signup.
You are absolutiely right.
The 30-day trial was introduced in November after we implemented some new features
and updated the look and feel of the application.
It was done to make sure all users have a chance to check out the new functionality.
If you would like to revert to the Free Plan, you will be able to do that after your trial period expires.