The price to mail a letter or your bills went up to 46 cents Sunday.
The U.S. Postal Service is also introducing its Global Forever Stamp, allowing customers to mail letters anywhere in the world for one set price of $1.10.
USPS first announced the price changes in October.
The new price is a penny increase from the previous price.
Forever stamps are always good for mailing a one-ounce letter anytime in the future regardless of price changes.
The price increase comes as the U.S. Postal Service continues to search for ways to diversify its business model, reign in legacy costs for retired postal workers and still provide service. Eliminating Saturday mail delivery has been discussed in Congressal hearings, as has closing certain postal locations.