Any money that you contribute to a Roth IRA can be withdrawn at any time without penalty. Earnings can be withdrawn after you turn 59 1/2 and the Roth has been active for 5 years. If you withdraw the earnings before then, you'll have to pay taxes plus a 10% penalty (unless you die, become disabled, or use the money (up to $10,000) for purchasing your first home). The earnings can also be used for education without penalty, but you'll still be taxed on the earnings.
I'm a fan of Vanguard's stock index funds because of their really low expenses, but other companies offer good ones as well. Vanguard's Total Stock Market Index, for example, covers practically the whole U.S. stock market but has a ridiculously low expense ratio of 0.19%.
Yes, please do the research. These are just suggestions.
