Mutual funds and exchange-traded funds, or ETFs, are valuable parts of a long-term investment stock portfolio.
Managed by professionals, they allow you to buy into companies and securities that you may not have been able to on your own.
But while both mutual funds and ETFs are considered low-cost investment products, they do cost money.
So before you sign up for any of them, the most important thing to look at is the expense ratio--an umbrella term that covers all sorts of costs and fees.