Hello and thank you for your question.
If you can tell me did will sellvana always be free
Sellvana is open source and will always be open source.
i want now use sellvana for my customer can im do that
Yes you can, since Sellvana is public beta at this time, make sure to run full comprehensive tests for functionality you require. Also, open source software is distributed as is, meaning we are not responsible for any issues you might encounter with it. At the same time I'll be glad to help you and make core changes and fixes as required.
And can you tell me what mean this user chat in top right corner when im put online i mean this inside administration panel.
This is an internal admin user chat, as an example of built-in PushServer functionality. Try to create a few admin users.
Hope this helps,