In one of our earlier businesses we did hot stamping and we used to give away business card magnets that had our logo with some cool looking foil designs.
Since we've changed the nature of our business, I put together these pocket folders made from 150 lb. card stock and blind debossed on the hot stamp press. It holds a business card, and a photo of what we do. Since I make them in-house, they're cheaper than small quantities of rack cards, and I can change the photo anytime I want without having to use up 10,000 brochures if they were printed elsewhere. The 4 x 6 photos are printed at WalMart. I use their one hour photo service so I don't get their www imprinted on the backs of them.
Total cost for the pocket folder, business card, and the photo is approx. 30 cents (for everything), plus a little bit of time to put them together...stamp, score, fold and glue. It's a little more elegant than just a plain business card, and customers are less likely to misplace them or throw them away.
They're also a great marketing tool since they are a little bit different. Whenever I hand one to a prospective customer, they usually look it over, rub their fingers in the debossed logo and then open it up and look at the picture, and that usually that starts a discussion. They seem to make cold calling a little easier.
They fit in a #10 envelope and are easy to drop in the mail.