Hi tamilnadu people, do you know this 'business secret' ?

The manufacturing price of a commodity irrespective of whether it is a grocery item, vehicle or anything... will usually be maintained as a great secret by the manufacturers. Well, I come to the point without boring. In our state, the prices at which grocery shops sell 'thuvaram parupu'(used for sambar) and 'ulundham parupu'(uruttu) is at its peak now being sold for Rs.92 and Rs.84 per kg approximately. This is the price in supermarkets and big grocery shops. So obviously, in small shops the price will be even more. What is the reason for the skyrocketing prices ? Before four years we were getting these items for Rs.30 per kg. What is the price at which grocery shop owners receive them ?