When it goes well:
Me: Sir! One banana, how much?
Him: Ten rupee.
Me: HA! See you later.
Him: (laughing) OK, OK, three rupee.
Me: (also laughing) (buys the banana).
(more reciprocal smiling)
When it goes poorly:
Me (to rickshaw driver): Sir! How much to the train station?
Him: 150 rupees.
Me: HA! The front desk at my hotel says 30 rupees is a good price.
Him: You have a mobile number for 30 rupee man? Go call him.
Me: (ashamed, speechless).