Plays generally do not have much merchandise, if any at all. Plays, unlike most musicals are not as "commercialized" to sell hats, t-shirts, programs, et al. However, plays generally will see window cards and maybe some smaller trinkets (buttons, keychains, etc) depending on the players in the game.
Some have had SP"s in the past...Like Laughter on the 23rd Floor. But for the most part...I'm not familiar with any others.
"Do you know what pledge time is, Andrew"? said the PBS Executive.
"Yes", Lloyd Webber replied. "My 50th birthday special must be one program that gets done a lot."
"No", mused the man from PBS heedlessy. "Not so much. Our Stephen Sondheim Carnegie Hall concert. That's a big one."
Spoons, forks and knives seemed suddenly to suspend their motion in horror, all around the table.
Successful plays (and even some "flops") usually have the standard 14x22 posters available. If they don't sell them in the lobby, Triton Galleries will have them.