Hello Norja!
The price is indeed annual and it provides you access to the plugin, updates for the year, and access to our support forums here on this site as long as the license is active.
You can certainly stop paying for the license after the year is up and the plugin will still continue to function — it will only prevent you from accessing updates and support until the license is reactivated.
Does that make sense and help answer your question? Please let me know. 🙂
Cheers,
Geoff