Starting Monday, you'll need a new stamp to mail a letter.

That's because the price of a first class stamp will increase one cent to 42 cents.

The price of the Forever Stamp will go up at the same time.

But if you already have a 41 cent Forever Stamp, those will still be good even after the rate goes up.

While the most visible change is the one cent increase for First-Class letters, according to the U.S. Postal Service, the changes are broader and include prices that could save you money when shipping packages:

Reduced Express Mail prices for items shipped to addresses closer to home.
Lower online postage prices for Express Mail and Priority Mail (domestic and international).
Volume Express Mail price rebates for frequent shippers.
Additional flat-rate box prices for Priority Mail.