for example the price of 1 kilogram sugar is 25 Rupees and a customers comes and say: hey give me sugar of 17 Rupees. and you do not have a digital scale in your tiny store what would you do ?

don't worry this app is for you !

this app says Rupees (pakistani currency unit) but it works for every currency unit... USD MYR EURO IND and all !...

NOTE: This app does not work like the physical digital scale you keep something on it and it calculates the weight rather it has the software of those scales. Means it only calculates and you have to weigh it yourself on a traditional scale.
SO please do not give bad reviews.