It depends on your risk profile, some people buy with only what is actually required (bare minimum) capital, eg. let us say Nifty 8600 CE is costing 80/- per lot = (80 * 25) = Rs. 2000/- so some will buy with only Rs. 2000/- in their trading account. Others will keep some extra money as buffer fund to absorb the shocks of market fluctuations. It depends entirely on you.
But, its always a good idea to keep some extra cash idle in your trading account.
If You are New to Trading. Better to stay away from Options.
Options will look attractive to Trade because of Low capital Requirement.
Best way to use Options is to Hedge Futures / Stock otherwise Only through Option Strategies.
Naked Option Trading is require Very Discipline and Lot of Experience in Market otherwise It may give Good Profit sometimes but In Most cases Total Capital get wiped out.
For NIFTY Options trading you need minimum Rs 20,000 (Do not take margin facility)
Take Qty-100 (4 Lots), this is a general standard for small traders. In the first trading day
of the month at the money options (ATM) premium will be generally around
Rs 200, So u need 200 x 100 (4 Lots) = 20, 000.
Its ideal. Iam doing this and many brokers and tip providers suggest Qty-100 only
NIFTY OPTION CALL PUT TRADING IS SAFEST AND BEST (FIRST BUY ONLY, NO SELLING FIRST)
Happy Trading