The FIDE Online Arena is fun and useful for both users who have a subscription and those who don’t. The subscription is for those who want to play online-rated games and work towards getting the FIDE Online Arena Titles recognized by FIDE. Playing rated games gives you a start in professional chess (here is where you can buy a subscription).
But you can also enjoy the Arena without having a paid subscription. You can:
Play unrated games and play for a World Chess rating;
Play in some unrated tournaments;
Analyze your games
For some of these features, you might consider registering for free — you will be able to save your game history and chat with friends and opponents.
You might be eligible for a free Pro subscription if:
you have subscribed at Old Fide Arena and your subscription has not expired yet. In that case please send the sync request to email@example.com
you are an offline player titled with WIM / IM / WGM / GM
Titled offline players will be assigned a free online pro membership.
To get the promo code please send the following information to firstname.lastname@example.org
A selfie where you are holding your ID (passport or driver's license will work perfectly)
your current FIDE ID number