Me: How much it cost now?
Son: Why you asking the price?
Me: Just to know, perhaps if you could achieve as the best in class, maybe I could buy you one.
Two weeks later
Son: well, the results has been announced, and I am the best in the class
Me: congrats! I always knew you always good in your education
Son: do you remember that you promise me a present?
Me: a present?
Son: yup, provided I could be #1 in class and you will buy the things
Me: what is that?
Son: a PSP