First, make sure that their job function is clearly defined and understood by you and them. What are you paying them for? Do they handle any support, or are the

First, make sure that their job function is clearly defined and understood by you and them. What are you paying them for? Do they handle any support, or are they only supposed to find new business? Depending on how big your operation is it might be helpful to hire a consultant or a friend who has experience with a sales force. It sounds like there might be an economical solution. do you know how much a dollar of ads earns vs. a dollar of base + commission? You could be up front about these numbers with your sales team and say "Look, I could pay you guys $100 and expect $200 in sales, or I could spend $100 in ads and see $500 in sales," and use those numbers to structure performance reviews and establish sales quotas.