Such coupons were a lifesaver for us Mumbaikars. With the introduction of such coupons we no longer had to waste our time to get tickets. Earlier Rs.1,2,3,4,5 coupons were available but now only Rs.5 coupons are sold. We just have to stamp the coupons as per the ticket fare.
For Ex: If i wish to go to Mumbai CST from Badlapur the fare is Rs.20. So I will stamp 4 coupons of Rs.5 whose total value will be Rs.20. The stamp contains information of the day and date and the starting journey station. It was hugely popular earlier but with the introduction of Atvm(Automatic Ticket Vending machine) it's use was limited. Railways also started discouraging it's use.