Follow CBSPHILLY Facebook  | Twitter

PHILADELPHIA (CBS) — Sending letters and packages through the post office just got a bit more pricey. On Sunday, the cost of forever stamps increased by five cents to 55 cents.

READ MORE: Do Spiders Dream? New Study Could Help Scientists Better Understand Human Sleep

The hike is the largest in U.S. Postal Service history.

Tourists Thrilled To See Popular Philadelphia Historical Sites Reopened

READ MORE: Nearly 40 Dogs Removed From Deplorable Conditions At South Jersey Home

Priority mail prices also jumped.

A small box, which previously cost $7.20 to ship will now cost you $7.90.

MORE NEWS: New Jersey Drought Watch: Residents Urged To Cut Back On Water Usage