For example, if you are using Google Ad Words to drive traffic to your site, take a look at the following interactive spreadsheet. This example shows a cost per click of 50 cents, and the resulting website visitors converting to a trial at the rate of 5%. Those trials are then shown converting to paid customers at the rate of 10%. What the sheet shows is that each customer is costing you $100 in just lead generation expense. For many consumer facing web sites, it can be hard to get the consumer to pay more than $100 for the service. And this cost does not factor in the marketing staff, web site costs, etc.
One of the more interesting things that this model shows is how rapidly cost of customer acquisition climbs If your leads require human touch to convert them, (compare cell B23 with cell B22.) This human touch can be as light as email follow ups, or as much as inside sales people doing multiple sales calls and demos. I have seen this cost vary from around $400 to $5,000 per customer acquired, depending on the level of touch needed.
Another shocking computation is to look at the cost of a direct field sales force: