Many moons ago, Robert Collier created the first dollar bill letter. And he used it during the 1920’s! Yes, that’s right. During the 1920’s he attached a dollar bill to thousands for sales letters which were marketing a non-profit organization.
In the 1920’s, a dollar was worth a little more then $11. So including printing and postage he spent, in today’s dollars approximately $11.50 per letter.
The original one dollar bill marketing letter was written by Robert Collier, and in his must read (and study like a maniac over and over) he claims that he got a 90% return rate for a charity sales letter.
Since that time a handful of marketers copied his idea to market local businesses, and products and services of all kinds.
The most recent examples I’ve seen using a dollar bill sales letter is for selling local webmaster services, carpet cleaning, financial planning, and now construction. I even saw a book at a local bookstore enclosing a dollar bill in the cover of their book which was about how to fold a dollar bill into all kinds of cool things (Origami).
I am sure there are dozens of other industries using it as well.