How much are postage stamps for 1-ounce and 1.2-ounce postcards?

According to the United States Postal Service, postcard postage stamps are available in two prices as of August 2014: $0.34 and $0.49. These prices are based upon the size of the postcard as opposed to its weight.

The maximum size of the $0.34 priced postcard is 6 inches by 4.25 inches by 0.16 inch. The maximum size of the $0.49 priced postcard is 11.5 inches by 6.125 inches by 0.25 inch. Any item smaller than the smaller-sized postcard cannot be sent via the U.S. Postal Service. Any postcards larger than the largest-sized postcard are priced as First-Class letters, large envelopes or packages. Postcards are sent by First-Class mail.