Check out this excellent post by David Skok from Matrix Partners on how to factor customer acquisition costs into your business plan. David recommends the lifetime value of your customer be 3x your customer acquisition costs, and all customer acquisition costs be recovered in the first 12 months, or else you will require excessive capital to grow the business.
David also offers an excellent spreadsheet showing the incremental costs of having humans assist in the sales process -- which creates interesting implications for everyone out there currently working in sales -- and offers several Sales 2.0 techniques to lower customer acquisition costs.
Highly recommended for entrepreneurs developing business plans, and anyone involved in starting a company, or in sales or marketing.
