Stamps are set to increase beginning Jan. 27, and it's the biggest price hike for postage since 1991.

Back in October, the U.S. Postal Service board of governors requested a 5 cent increase to the forever stamp, upping the price to 55 cents. The USPC said the change would also reduce the additional ounce price of letters.

The Postal Regulatory Commission approved the price changes last month.

New prices for postage

Forever Stamp: 55 cents

Metered letter: 50 cents

Additional ounce: 15 cents

New prices for Priority Mail

Retail small flat rate box: $7.90

Retail medium flat rate box: $14.35

Retail large flat rate box: $19.95

Retail large flat rate box APO/FPO/DPO: $18.45

Retail regular flat rate envelope: $7.35

Retail legal size flat rate envelope: $7.65

Retail padded flat rate envelope: $8