The cheapest broker is Finvasia with Absolute Zero Brokerage.
For option scalping, Finvasia is BEST. When u scalp using multiple buys especially using buy average and partial profit booking, Zero Brokerage is the best choice as u have the lowest fixed break even.
Finvasia will reduce your breakeven, especially in options you can buy 1lot+1lot+1lot.... can average 1000 times with the same lowest break even, there is no Rs 20 per trade..brokerage is ZERO.
However, for Future intraday leverage is less. U'll get 50% for MIS, BO, CO all. No extra leverage for BO-CO. Although, there is intraday paid leverage scheme. This is their alternate ways of earning, u don't actually need to use it.
If u r scalping with options(long side) then u don't require any leverage, then Finvasia is the best choice.
However, for Future, u may not like them if u r currently using BO-CO with extra leverage.
Finvasia does have a thread in TJ, read the posts/review there to know more...