The price of stamps changes when the Board of Governors of the United States Postal Service votes to increase rates. This decision is based on the need to fund the department.
As of June 2014, the price of a first-class stamp is $0.49, which was the result of a $0.03 increase voted on by the Board of Governors in January 2014. Prior to any rate increase becoming effective, the Postal Regulatory Commission (PRC) must review and approve the increase.
Postal rates are reviewed for increase on an annual basis by the Board of Governors as part of their budget review of the Postal Service. If there is a shortfall in the budget, a rate increase is suggested.