Ask them to share costs with in-kind services, such as printing the program, invitations, free ads in their publications. Make plans for getting advance and follow-up coverage in the media. Ask local merchants to donate cheese, wine, goodies for a pre-events reception. Be sure to give credit on the program, in news releases and during introductions. Make a fuss.
Authors like to be catered to.
Offer to entertain them at cocktails, dinner, a quick tour, etc. Many authors enjoy talking to a writing class if time permits. Make sure you invite the county chair, mayor, chancellor, heads of departments, local council representatives-the men and women who make decisions concerning the library. Often this makes an appropriate event to honor someone who has made a special contribution to the library. Remember, most authors are there to sell books.