Kundan Singh — high charges by railway station vendor

Address: Chennai, Tamil Nadu

i am a frequent traveler from Chennai suburban, going from home to college and again back in evening when ever i go to Chennai central suburban station i used to buy drink water snacks chips.And there i find that rate fluctuates shop by shop, normally they charge

sno items mrp charge by vendors /stall of irctc

1. coldrink 25 30
2. fruiti 30 35
3. chips 15 20
4. water 15 18

as, i understand for 3-5 rupees no pay attention there but for frequent traveler like me suffers a lot.
kindly, take appropriate action against them.