Much like building your referral program, marketing to your center of influence is widely underutilized.

We had a strange influence system once before, and long discussion about it.

As you sphere of influence grows, you should make sure that the growth comes from the kind of people who are positive and have goals and beliefs that are in line with where you want to go.  

Can you use your networks and influence to find her a cheaper place?

The purchase price influences that estimate, but the estimate is not set to the purchase price, and the estimate is typically less than fair market value. 

Always try to find a "win-win" when negotiating with anybody, and always try to appeal to them.Best book ever: How to Win Friends and Influence People.

Not discounting the value of BP or net working at all, but subjective opinions are influenced by many variables, attitudes, agendas and assumptions.My sandwich was good, it may have put me in a better position to discuss another business transaction later that day, so it may have contributed to some success there, I didn't account for that.

Sometimes, our environments (friends, relatives, circle of influence) do not encourage success.

It is far and away my favorite that I have listened to at least 6 times  (TIP: the good stuff starts at about :25min) That one has had the most influence on me trying to pre-screen on the phone. 

@Michael Quarles what is a "center of influence" lead source?