Definitely Zerodha is cheapest in charge wise and service also 80% good, I used Kotak which is cunning(As soon as u do funds transfer, immediately they allow temporary funds but later they dont credit that amount. out of many funds transfer 2 times that fellows not added, once amount Rs30k, another time around 70K in 2008.) Then I closed immediately. Cost also high as ICICI.
Zerodha charges Rs20 for any size of buy, in Kotak/ICICI direct if u buy an options u need to pay Rs100 but in Zerodha Rs20 max whether u buy 1 log or 10 lots.
Only I dont like is that unnecessary many fields in page display, u need arrange them properly which is not seen in ICICI direct .
