Hi, Go for Zerodha!!
First they wont charge on % basis. They charge on per order basis- Rs.20/order. Even if your order is executed in pieces at different times, your total brokerage will be Rs. 20 only.
Second, they have a tool called bracket orders. With this while entering the position itself you have to define your SL and TGT. There are additional features to it as well. With Bracket Order, you can trade 1 lot of nifty with just 5000 to 6000.
Last but not least. You can refer your friends and earn 10% of their brokerage in your kitty. Please check their website and please ask me back my code before you open your account!!
All the best for your trading!!