always asks more money above the MRP for cold drinks

Almost all shopkeepers in my city asksfor extra money above theMRP for chilled drinks.i observed every time when i went 2 buying cold drinks like mazza, sprit,pepsi and etc.. MRP on the bottle is Rs.9 but all shopkeer in my city Nandgaon Tal-Nandgaon Dist-Nasik. PIN 423106 state-Maharastra takes Rs.14 to Rs.15..