I also ask "Do you mind if I ask where you got my name" 90% of my work comes from referrals. Referrals are generally not price sensitive and want to hire me because a friend, co-worker or family member told them about the job I did for them.

If they say they found my name in the phone book and are checking prices, I cheerfully tell them if they only want the lowest price I can tell them who to call and they won't waste any more time. My wife thinks that is running off a potential customer but the price shoppers are not the type I want to work with.