Charles Andermack, a font designer who works under the nom de lettres Chank Diesel, likes to brag that one of his custom fonts has been sitting at the top of the New York Times best-seller list. He created Truck King, the font used to typeset “Jon Scieszka’s Trucktown Smash! Crash!” an illustrated book about trucks. Mr. Andermack’s design firm, Chank Fonts (chank.com), builds custom fonts for advertisers, book designers or corporations looking to capture a special look or style.

While Mr. Andermack’s fees can run into the tens of thousands of dollars for full families of fonts with all the diacritical marks and permutations, he can turn anyone’s handwriting into a font for $200. These custom fonts, also available from other sites like vletter.com, are popular not only with scrapbookers but also with professionals like real estate agents who want to add a personal touch to their letters.