Find something you know to get started. It's much easier when you keep the barrier to entry lower. I know and work in tech, feel the industry as a whole is still growing, and so I invest in tech.

AMD is cheap right now and likely doesn't drop much more (unless something big on the CPU scene happens). Intel is already healthy but consistently growing. I buy both, because the demand for their products isn't diminishing, and they both grow over time.

Lots of opinions on the market but I think he wants you to learn and understand it for yourself. It's popular to bash on people owning stock in your 20s, until you hit your 30s or 40s, hopefully a little success in a career, and have a little extra money left over each check. After a while you realize the $4/mo your bank is giving you in interest is ridiculous when a few hundred dollars in AMD stock would have earned $10 on Friday alone, as it did me.

It's gambling at the end of the day, so only put in what you are willing to lose.

Good luck!