(from Dick Eastman’s daily newsletter · June 23, 2015)
Years ago, postcards cost 1¢ to mail within the U.S. Postage was temporarily raised to 2¢ from 1917 to 1919 to cover the cost of World War I and the increase was rescinded after the War. In 1952, the required postage was raised to two cents and has slowly escalated ever since. Today, mailing a postcard cost is 34¢. (Reference: https://en.wikipedia.org/wiki/History_of_United_States_postage_rates)
Over the years, many postcards were printed with view of a town or other area, then sold in stores within that town or area. Many of these postcards have been preserved and often provide an interesting glimpse of what life was like in “the good old days.” Possibly your ancestors saw these same views in person.
USGenWeb has a rather good collection of penny postcards available online. The scenes vary from pictures of the downtown business area to residences to schools to people at work. Railroads seem to be featured often in these old pictures.
You can view the USGenWeb collection of postcards at US GenWeb Penny Postcard Collection. Click on the state and then on the county name to see old penny picture postcards from that area.