Investing in stocks, directly, carries huge risk. When Satyam Computers scam broke out the stock price came down to 10% of the value on the previous day! So if one has invested only in Satyam almost all her money would have been wiped off. There is lot of research involved in selecting the stock. Unless you are not good at researching and monitoring daily, you should not invest in stocks directly.
In order to invest directly in stocks, you need to open a trading account and DP account with a stock broker. The DP account has annual charges which can be about Rs.400 to Rs.600 per year. Apart from that there will be brokerage charges of 0.3 to 0.5% of the value of purchase or sales. There will be service tax on the brokerage and security transaction tax. Therefore if you invest Rs.25000, in stocks the cost will be minimum 2%of the investment value. For Rs.1 lac the cost could be about 0.8%. So opening a trading account to start investing in stocks with small amounts is not a good idea.
It is better to start investing through equity mutual funds.