the government put a CAP on the PRICE of RICE..because it keeps changing
cap (~ a hat). Cap price rises so you change your mind to buy one
cap+rice: cooked rice on your new wearing cap? sudden impulse will come to your mind.
My favorite car is a Caprice: So I remember it as: "I HAVE A CAPRICE FOR CAPRICE"
Cal saw the low price of rice and immediately was impulsed to buy some!