It will cost a bit more to mail letters and parcels starting Monday. A first-class letter will go up 2 cents to 41 cents.

But there is some good news – folks will be able to buy “forever” stamps that remain valid regardless of any increase.

While the new rates take effect Monday, most post offices are closed Sunday so officials say items dropped in a box that won’t be collected until Monday should have the higher postage on them.

But, when rates change the agency usually allows a little leeway, and it doesn’t plan a rash of returns for insufficient postage.

While the first-class rate will rise from 39 cents to 41 cents for the first ounce, people sending heavier letters will see a reduction in the price. That’s because each additional ounce will cost just 17 cents, down from the current 24 cents.

The first forever stamps are selling for 41 cents apiece, but they won’t have a price printed on them and they will remain valid for sending a letter regardless of any future increases.

Aside from vending machines, there are other options on where to buy stamps. There’s the option to order stamps by mail by contacting your mail carrier or calling (800) STAMP-24. Stamps are also available at some retailers and can be ordered at www.usps.com.