Tabula Rasa is starting a referral program. Recruit a friend to pay for a month's subscription and you get an extra month added to your account.
The AFS is looking for new recruits, and now YOU can aid in the war effort, and get a FREE Month Credit* to Tabula Rasa! If you refer a friend and they purchase a standard account and pay for one month of subscription to Richard Garriott's Tabula Rasa®, you will be automatically credited with one month of free game time!
Sounds like a good deal. You can read the rest of the instructions at the link above.