ICICI charges 0.1% of the contract price. Here the contract price is determined by (strike price + premium)*volume. To make it simple, if you buy 1 lot of call/put option of Nifty 3100 strike price by paying 80 premium, the brokerage will be (3100+80)*100(since Nifty lot size is 100)*0.1% which is Rs.318/-.
Over and above this brokerage, service tax and STT are applicable.