Maybe you're not the savvy-investor type, but you have an interest in investing for some extra cash. It's easy and care-free; you can manage your own portfolio with ease by following these two steps:

Pick a mix: You'll need to figure out how you will divvy up your money between stocks and bonds, after deciding how much money you have, or want, to work with. You can use online tools to fine-tune a mix for your age and appetite for risk. However, there is an easy rule of thumb if you'd like to stick to the simplest decisions: to decide how much you should devote to stocks is to subtract your age from 120. So if you're 40, put 80% of your long-term savings in stocks and 20% in bonds. If nothing else, this simple formula ensures that you'll own an ample amount of stock when you're young and can take more risks. Every year, subtract your age from 120 again and adjust the mix as needed.

Buy index funds: For an investment that doesn't require constant care, the clear choice is an index fund. With a single fund, you can own virtually the entire stock or bond market. No index fund will ever top the charts, but history suggests that over the long run they'll earn a better than average return. You can build a perfectly adequate portfolio with just two funds: a total stock market index fund and a total bond market index fund.