I am not sure what you mean by freebies, but if you go to one of those big wedding shows you can go around to all the different vendors and some of them will let you taste food or cake and give you cards/samples of their work, or DVD's showing their wedding video-ography, samples of their music etc. Stuff like that. But those are really only worth it if you go to one in the area of where you are getting married because all of the vendors are local and there is usually a fee to get in, but there are sometimes door prizes.
Tell them to go online to Martha Stewart Weddings or the Knot or Wedding wire to get started. Have fun!