Do not let your invoices go out the door unadorned with marketing messages. The cost of printing these messages has gone through the floor, but if your small business doesn't have the resources to merge-print marketing messages on the bill, consider adding a personal message or a clipping of a new item or offer to the invoice. To the big ones, anyway.
Wall St. Journal: Bills Make Room for Advertising, 2007-Oct-16, by Christopher Lawton
Humana Inc., a health-benefits company in Louisville, Ky., began using transpromotional marketing last year by including specific messages in the health and benefits statements it sends out to its 4.5 million Medicare members. In the past year, the company's customer retention rate has jumped 17% thanks to its new statements, says Chris Nicholson, Humana's strategic communications director.