As a recovering sales manager, I have always laughed at the proposition that “sales people are coin operated”. Notice that I said I laughed, not that I didn’t agree.
What would you say if I told you that quite a body of research is telling us that “extrinsic motivation” (e.g. bonuses and commissions, carrots and sticks) actually makes performance worse, not better. On the other hand, “intrinsic motivation” (I work because I love what I do) is the more durable motivator, especially in the 21st century.
I’m reading Dan Pink’s book, Drive, and I recommend it highly. If you’d like a compelling TED video on this same topic, done by Pink in 2009, check out this YouTube video.