On April 26, 2015, the cost for mailing postcards rises from 34 to 35 cents, and costs for international letters rises to $1.20 from $1.15, according to USPS. Mailing a 1-ounce letter still costs 49 cents, but costs for additional ounces rise from 21 to 22 cents.
As of January 2015, USPS doesn't plan on increasing costs for domestic Priority Mail or Priority Mail Express services. However, on April 26, 2015, Priority Mail International costs rise 6.8 percent, with plans for Canada to be zoned. Priority Mail Express International costs are set to rise 6.7 percent, and flat-rate pricing remains available.