Picture postcards with Halloween greetings began to appear in the early 1900s. They range from simple cards with "Happy Halloween" to elaborate embossed and multicolored cards with gilt trim. This is a "mechanical" card—the girl's arm can be moved up and down so the jack-o-lantern can cover her face. It was designed by Ellen Clapsaddle (1865–1934), a commercial artist and one of the most popular postcard designers of the time. The 5 1/4-inch by 3 1/2-inch postcard was printed in Germany and sold for $285 at a recent Hake's auction in York, Pennsylvania.

Some collectors look for Halloween postcards featuring a particular subject—witches, pumpkins, black cats, children playing games or children being frightened. Others favor cards by a favorite illustrator or publisher.

Find prices of other Halloween collectibles in the FREE price guide at Kovels.com and in our newest book, Kovels' Antiques & Collectibles Price Guide 2012, available now.