The cost of First Class Forever stamps are going up 1 cent effective Sunday, January 21st from 49 cents to 50 cents.

Additionally, postcard stamps will increase by a penny, going from 34 cents to 35 cents. Certified mail will be increasing by 10 cents from 3.45 to 3.55. Priority Mall Flat Rate Boxes are going up 5 cents. Small Boxes are going from $7.15 to $7.20; Medium Boxes from $13.60 to $13.65 and Large Boxes are going up from $18.85 to $18.90