Currently, Warhammer online 10 days trial is available, here is a brief introduction. Warhammer online free trial will lasts for ten days from the moment you create your free trial account, the 10 days will continue to count down whether you're logged in or not.
Some restrictions in the trial version:

All trial accounts are restricted to Tier 1 content and Capital Cities.
Trial accounts may receive mail and purchase from the auction house by Warhammer online gold; however, they cannot send mail or create auctions.
Trial accounts are limited to designated servers. If you'd like to play with friends on other servers, you will need to purchase a retail copy of the game and transfer your character to their server (or create a new character on their server). All characters Rank 11 and under on purchased accounts have access to unlimited transfers, with a max of one transfer per day. Please note that you can only transfer characters to the same server type as the server you created your characters on (Core, Open RvR, and Roleplay).

You may play the trial on a computer that has the full game installed, but the free trial restrictions will still apply. If you cancel your account, it will not lock you out of the trial, you will be able to play until the end of your free trial period and you can still earn WAR gold as you want. After that, the full version of the game must be purchased, and you will have to enter the Product Registration Code and billing information in order to continue to play.

The full version of WAR may be purchased from any major retailer that sells PC games. A full list is available here. You will need to enter the Product Registration Code in the Account Center to upgrade. Once your account has been upgraded, you can run the trial patcher to automatically download the complete game files.

The characters you created (and all their gear, Warhammer gold) remain on the server waiting for you to purchase the game and continue your journeys across the battlefields of WAR.