This is an old post I feel requires some more love for completeness.
Though several responses have mentioned the inherent risks that currency speculation, leverage, and frequent trading of stocks or currencies bring about, more information, and possibly a combination of answers, is necessary to fully answer this question. My answer should probably not be the answer, just some additional information to help aid your (and others') decision(s).
Firstly, as a retail investor, don't trade forex. Period. Major currency pairs arguably make up the most efficient market in the world, and as a layman, that puts you at a severe disadvantage. You mentioned you were a student—since you have something else to do other than trade currencies, implicitly you cannot spend all of your time researching, monitoring, and investigating the various (infinite) drivers of currency return. Since major financial institutions such as banks, broker-dealers, hedge-funds, brokerages, inter-dealer-brokers, mutual funds, ETF companies, etc..., do have highly intelligent people researching, monitoring, and investigating the various drivers of currency return at all times, you're unlikely to win against the opposing trader. Not impossible to win, just improbable; over time, that probability will rob you clean.
Secondly, investing in individual businesses can be a worthwhile endeavor and, especially as a young student, one that could pay dividends (pun intended!) for a very long time. That being said, what I mentioned above also holds true for many large-capitalization equities—there are thousands, maybe millions, of very intelligent people who do nothing other than research a few individual stocks and are often paid quite handsomely to do so. As with forex, you will often be at a severe informational disadvantage when trading.
So, view any purchase of a stock as a very long-term commitment—at least five years. And if you're going to invest in a stock, you must review the company's financial history—that means poring through 10-K/Q for several years (I typically examine a minimum ten years of financial statements) and reading the notes to the financial statements. Read the yearly MD&A (quarterly is usually too volatile to be useful for long term investors) – management discussion and analysis – but remember, management pays themselves with your money. I assure you: management will always place a cherry on top, even if that cherry does not exist. If you are a shareholder, any expense the company pays is partially an expense of yours—never forget that no matter how small a position, you have partial ownership of the business in which you're invested.
Thirdly, I need to address the stark contrast and often (but not always!) deep conflict between the concepts of investment and speculation. According to Seth Klarman, written on page 21 in his famous Margin of Safety, "both investments and speculations can be bought and sold. Both typically fluctuate in price and can thus appear to generate investment returns. But there is one critical difference: investments throw off cash flow for the benefit of the owners; speculations do not. The return to the owners of speculations depends exclusively on the vagaries of the resale market." This seems simple and it is; but do not underestimate the profound distinction Mr. Klarman makes here. (and ask yourself—will forex pay you cash flows while you have a position on?)
A simple litmus test prior to purchasing a stock might help to differentiate between investment and speculation: at what price are you willing to sell, and why? I typically require the answer to be at least 50% higher than the current salable price (so that I have a margin of safety) and that I will never sell unless there is a material operating change, accounting fraud, or more generally, regime change within the industry in which my company operates. Furthermore, I then research what types of operating changes will alter my opinion and how severe they need to be prior to a liquidation. I then write this in a journal to keep myself honest. This is the personal aspect to investing, the kind of thing you learn only by doing yourself—and it takes a lifetime to master. You can try various methodologies (there are tons of books) but overall just be cautious. Money lost does not return on its own.
I've just scratched the surface of a 200,000 page investing book you need to read if you'd like to do this professionally or as a hobbyist. If this seems like too much or you want to wait until you've more time to research, consider index investing strategies (I won't delve into these here).
And because I'm an investment professional: please do not interpret anything you've read here as personal advice or as a solicitation to buy or sell any securities or types of securities, whatsoever. This has been provided for general informational purposes only. Contact a financial advisor to review your personal circumstances such as time horizon, risk tolerance, liquidity needs, and asset allocation strategies. Again, nothing written herein should be construed as individual advice.