Come Sunday, it will cost you a penny more to send that card to grandma.
First-class stamps are going up to 46 cents. Postcard postage also rising a penny to 33 cents.
Since 1885, when the price for the first ounce of a first-class letter was two cents, rates have increased 24 times.
The hikes come as the postal service still pays into future retiree healthcare benefits and consumers increasingly migrate to online services.