The United States Postal Service increased the rates for mailing some items Sunday. Mason City postmaster Alan Steckman says the price for a first-class stamp will remain 34-cents, but the cost of a postcard is going up a penny. It’s the first increase in the cost of mailing a postcard in six years. A postcard stamp now, today, costs 21-cents. The cost of mailing heavier letters will now cost an additional 23-cents per ounce. Steckman says rates will change for businesses, and more information about the rate changes can be found on the Internet.The postal service website is www.usps.com.