The postage for a first-class letter is being increased two cents, to 41 cents.
U.S. Postal Service officials say items that were dropped in a box over the weekend and won't be collected until today should have the higher postage on them, but the agency usually allows a little leeway, and doesn't plan a rash of returns for insufficient postage.
Also today, the Postal Service will start selling “forever” stamps that cost 41 cents now, but will remain valid regardless of any future increase.
Postmaster General John Potter has said that even with the higher prices the agency expects a deficit this year as it struggles to compete in a swiftly changing communications market.