Customer Relationship Management (CRM) systems come with a heavy cost and sometimes disappointing results. Forrester Research says that large companies typically can spend between US$15 and US$30 million a year on complex CRM systems. The Meta Group estimates that 55 to 70 percent of CRM projects fail to meet their objectives.With numbers like those, smaller businesses are unlikely to invest in CRM. However, the Booz Allen Hamilton website Strategy+Business, offers a common sense approach to CRM. They point to the good old invoice as a respository of much data that can be analyzed and manipulated into a CRM approach. Their suggestion is to pull data from invoices and load it into common database software such as Microsoft Access.For most smaller companies, this homegrown CRM system is just the ticket. We recognize that it could be labor intensive in the beginning and require disciplined ongoing data collection. But the results could be stunning. And the invoice is just the start. Think what you could do with the information in salespeople's heads and the data acquired by customer service interaction.If you're selling consulting services to small businesses, think what you could do with a rudimentary customer service system such as the one described by Strategy+Business.