How many times would this have happened to you ? You are at a retailer buying a phone, or some consumer durable (TV, fridge, AC, DVD player, etc) and the retailer says that you need to pay 2% extra if you are paying by credit card. You really don’t have that much cash in hand, and do not have the patience to go back and get the required cash. So, you grumble a bit, and then end up paying that 2% extra. Well, congratulations, you also gave the shopkeeper the saving he wanted at your expense.
A credit card is supposed to cost the retailer that 2-3% of the total amount (that amount being the amount he needs to pay his bank, your credit card company and the Mastercard/Visa company). And why does he pay that much money ? Well, he no longer has to worry about whether the money he is getting is genuine or counterfeit, he is liable to get customers who don’t have cash in hand but want to buy the item (thus ensuring higher sales), and he no longer has to worry about handling cash (thus avoiding the risk of theft).
Read some text from this article that also advises against paying the 2% extra:

For some years now, it has been observed that certain merchant establishments-especially budget jewellery, electronics and grey market outlets-ask customers to shell out about 2% extra for purchases with credit cards. All card-issuing banks TOI spoke to, and the Credit Card Holders’ Association of India specified that merchant establishments cannot do so.
Says Sachin Khandelwal, head, cards group at ICICI Bank, “Typically, there is a fee a merchant agrees to pay for a terminal… If a merchant tries to recover it from customers, they must walk out.” Khandelwal also advises consumers to report such cases to credit card-issuing banks. “We may then blacklist them (the outlets) and remove our terminals.” An official at another card-issuing bank adds, “It is a bad practice. If someone charges 2% above MRP, you should report it to a consumer forum, irrespective of the value.”

Given all the advantages that credit cards enjoy, there is absolutely no reason for consumers to pay extra. All you have to do is exercise your right, and stand firm.