Sell them something.
My game is to interrupt them as quickly as possible with the question, "Never mind that. Do you drive a car? I can save you money on your car insurance."
When they say they don't drive, you can ask them whether their Wife / Friend / Mum / Dad / Brother / Sister etc would like to save money on their car insurance. Eventually, once you've exhausted all avenues, I finish the conversation with, "I'm very sorry. It would seem that I'm not going to be able to help you today."
On numerous occasions, they have THANKED ME! and hung up. That's my win.