The best investment for your money is largely personal preference. If you’re looking for an investment that gives you more immediate access to your funds, a money market is the best option for you. As long as you don’t go over your transaction limit, you can withdraw from or deposit money into your account with ease.
You won’t have this same luxury with a CD. Once your money is in a CD, it’s there until the term is up. If you’re willing to part with your money long-term (two years or more), you’ll make a sizable return on a CD investment. But if you don’t want to invest for that long, a money market will usually offer you a better interest rate than a CD with a shorter term.