Customer acquisition cost (CAC) is the amount of money a company spends to get a new customer. It helps measure the return on investment of efforts to grow their clientele. CAC is calculated by adding the costs associated with converting prospects into customers (marketing, advertising, sales personnel, and more) and dividing that amount by the number of customers acquired.

Combining Email Marketing with Other Types of Marketing
Whether you choose to do your marketing online or offline, one thing does not change. This is the concept that no single marketing strategy will be as effective as a combination of two or more marketing strategies.