There is no benchmark quantity for the minimum amount required to invest in share market.. you can even start your investment with Rs 100.. since you say that you are a beginner, please do a systematic study about the market and its behavior. Be aware of the terms and conditions (the commission charges of your agent, details regarding tax to be paid etc etc) before you even make your first investment. Since you are a beginner, choose a handful of companies (which have a good brand name, showing a good turnover and profit and its reliability), make a study on it ie its behavior over the past few months of trading session. Once you are done with all these, you go ahead and make your investment..
As a thumb rule, never invest more than 30% of your savings in the stock market as this is a volatile one and you cant get back your invested money as and when you require..
In case you want further details, there are exams conducted by NSE for all levels (right from beginners to agents) where you can get registered, get information and clear those exams. This might be a good exercise for you.. you can get further details in.
All the best with your investment.
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