I was told (correct me if I am wrong) that vanity plates are purchased for 5 years.
@Nuisance : I get the "state-sponsored" (i.e., created outside of the very for-profit "myplates" system) charity plates, which are renewed annually. Each year the cost is $30 for the plate design ($22 of which goes to the charity), and another $40 if you want to personalize, for total $70/year (with again $22 of that going to the charity the plate is for). While being identifiable is a definite downside, it is fun to try to make people laugh.
Looks like the personalized MyPlates ones are $150(!!!) if you order for one year or $450 for 5 years (so $90 annually).
You can also get "background only", with lots of cool charity designs (and also the big sports teams) for just the extra $30 a year. Scroll down here to see options:
www.myplates.com/des ign/background/passe nger/sea-turtle?attr ibute=44+47+46