Received a small inheritance what do I invest it in?

I'm a student and I just inherited a small sum (1500$). For once in my life I don't have to pay anything to anyone back so I want to invest it. I want to play it safe, maybe averaging 9-10% earnings per year over the span of 20+ years. Since I finished paying a lot of stuff and I should have some extra money and I wanted to put in 200$ per month. The problem is that I don't know anything about trading and investing in general. I wanted to put it in a S&P500 but some friends said it's a bad moment because it might collapse soon. What should I put this money on? Is this 9-10% earning doable and as free of risk as people led me to believe?