us mail cost of postage stamp
Summary of the 2015 Postage Rate Increase: 1  First Class Mail Letters (1 oz.) will remain the same at $0.49 when purchased at the Post Office. 2  Each additional ounce will cost $0.22 (up one cent from 2014). First Class Package Service will see an increase of 5.1% in 2015. 2  Commercial Base (online postage) rates will start at $2.04 (1 oz.), up $0.11 compared to 2014. 3  Priority Mail rates are NOT INCREASING in 2015. 4  Commercial Base (online postage) rates will continue to start at $5.05.