The trial includes access to the full game but it is time-limited to 72 hours. Don't delay once you've created your account, either, as the clock starts ticking "as soon as users sign up," according to Trion's press release. There's also an EGO rating cap (200). Finally, you'll be able to carry over all your progress, rewards, and store purchases to the full game if you decide to pony up for the client once the trial period ends.
[Source: Trion press release]