I have been doing this on the very few bills I still mail (I am addicted to online bill pay, but dentist bills, medical bills, we still mail in) I had a dentist appt today, and the secretary caught me on the way out and said she wanted to order a few things, said she had been saving my card that she rec'd with my payment but she couldn't find it! Lucky for her I carry some mini catty's with me, so I gave her one of those, and told her about the online catty show I'm running for anyone who wants to place some holiday orders but doesn't want to hold a show, etc. And DH had the audacity to laugh at me when I told him I was putting biz cards in with his medical bills! He's learned not to question me since then (he also used to hate my catty tote b/c I "have so many nice bags, why carry that thing around?" until the day someone at CVS starting asking me about PC!) It was a beautiful thing when I called him on the way home from the dentist's office and told him I made a sale from putting my biz card in with my last dentist's bill!