The trial accounts also can only use public chat channels, you can't post on the forums or send in-game mail either. Upgrading to a full account slays these pestering restrictions dead.
You get to try out an MMO world full of peril and adventure for free, what's wrong with that? In order to get trial access you'll need toon Funcom's site. We at Age of Conan when it was fresh-faced, but it's since undergone some major change.
As soon as you login for the first time your trial period begins. For Crom!