3 for 1 Sale.
I've used props infrequently in my games through the years. When I do use one there tends to be a really compelling reason leading me to put forth the extra effort. I once wrote a very schizophrenic poem with weird spacing that was actually a map (and the content of the very Post Modern poem hinted at which branches of the cave should be taken). The map was of a hidden region in the second layer of Pandemonium and ripped quite literally from the the diary of a madman. If I can find it, I'll post it over on the G+ Map-Making in Games page. But that's not really the point. The point is thus: should I bother to make/use a prop, it's kind of a big deal. RPGs are, to my mind, primarily an exercise in words.
Which brings me to the crux of what is quickly becoming a full-on scattered-ass rant; the best prop I've ever used is a simple 50¢ notebook. If you are running an investigative scenario, buy one for each of your players.
|Tiny Notebook Still Life #1, Actual Prop w/ GIMP|
As we (GMs) all know, player note-taking is usually infrequent at best. Vital knowledge is rarely ever committed to paper (but for some reason the name of that random barkeep from the first session usually is *sigh*).
I gave these tiny notepads to my players for a stupid-supers game (ala The Tick and Mystery Men); they wrote it all down. The players seemed to actually enjoy noting down the ridiculous clues and facts of the case at hand. We've all watched enough police procedurals to know that all detectives write down important things in tiny notebooks. Oddly enough, when given tiny notebooks and a crime to solve, players will also write everything down.
The layout of my for-money nerd game publishing debut piece, "Wretched Grasp w/ Bonus Mini-Adventure Wretched Beginnings" is coming along swimmingly. I'm in the early stages of laying the thing out. If I can stop obsessing over unimportant design minutia, I should have it for sale before too long.