(CNN) -- Some mailing costs will go up on Sunday, according to the Postal Service.
A stamp for a first-class letter under an ounce will remain 44 cents, the Postal Service said.
Mailing costs for parcels and magazines will be among those affected. Rates to send letters and packages to various countries will also increase.
The cost of mailing a postcard will also go up by a penny -- to 29 cents.
The U.S. Postal Service, which suffered a net loss of $8.5 billion in fiscal year 2010, announced the changes three months ago.
"Working together as an industry, we can address continuing economic challenges in a way that allows the Postal Service to generate much needed revenue while being more responsive to ongoing customer needs," Postmaster General Patrick R. Donahoe said earlier this year.
The Postal Service said the hikes will bring in $720 million if implemented for 12 months.