Is it really FREE?! For how long?
Yes, it is really FREE and for as long as you wish! The account creation needs simply a valid email address and a password.
No payment-card is required and your account is functional for as long as you wish to keep it. It is not a trial account with some short-term validity. It does not expire, even if you never subscribe to a paid-plan subscription. It is a functional account with no expiration date.
Wrapping this up, the service is FREE and only if the user wishes to support the platform and get also extra functionalities is welcome to subscribe.