A reminder: stamp prices are on the rise, as of Sunday.

The cost to mail a letter will go up slightly when postal-rate changes go into effect on Sunday, according to the U.S. Postal Service.

Stamp prices will increase one cent, from 45 cents to 46 cents, to mail one-ounce letters, effective Jan. 27. The cost for letters weighing more than one ounce will stay the same, at 20 cents for each additional ounce, an announcement from the postal service says.

Postcard stamps will also see a one-cent increase, from 32 cents to 33 cents. Letters under one ounce mailed anywhere internationally will cost $1.10, the announcement says.

Those looking to save a few cents could stock up on the postal service's Forever stamps (costing 45 cents until the one-cent increase on Jan. 27), which are usable even after stamp prices change.