$100 is WAY too little money for gambling in the markets.
First, make sure that you have at least 6 months' savings that you can access in case of an emergency. NEVER use this reserve for gambling.
Then, and only then, start reading a LOT of legitimate books on investing, stocks, etc. IGNORE sales materials prepared by schlock brokers that offer deals on precious metals, margin, and other gimmicks. If possible, go to an adult education course on investing.