To maintain your certification (be it PMP, CAPM or PgMP), you have to meet the ongoing requirement for Professional Development Units. For the budget conscious of you out there, there are plenty of ways to fulfill your 60 PDUs within a three-year cycle that cost no money.
Congratulations! You've passed the PMP exam! But your work isn't finished...now you need to shift your focus to earning the 60 PDUs required to maintain that credential you worked so hard for. If you follow this six-step plan of attack, you'll be well on your way.