Penny stocks are low-priced stocks that typically have low market capitalization and liquidity and are often listed on smaller exchanges. In India, penny stocks can be priced below Rs 10. Some top Indian penny stocks include Vodafone Idea Ltd, NHPC Ltd, and Morepen Laboratories. Penny stocks are very risky investments due to their high volatility, potential for pump-and-dump and short-and-distort schemes, and mistakes made by inexperienced traders such as lack of a trading plan or getting caught up in hype. However, penny stocks also offer the potential for high returns due to their low costs.