It is still free but due to some rules like evil points IP is under observation then it is possible you to pay some small fee otherwise Bitcoin talk is free and huge community forum.
How do they determine those "evil IPs" and is paying really the only way out of it? Seems weird to me since I don't think newbies would want to pay just to be able to start posting newbie posts...
Honestly its hard to know if you didn't register so to determine that your ip has evil points better to try register with new account if you can't able to post and you have red bar upper of forum page including the note "how to enable your posting in forum"
Its a sign that your ip is ban or your ip has evil points..
Also check this thread by admin
https://bitcointalk.org/index.php?topic=1215937.0It includes the map which where you can see what place had evil points..