Controlling 5 DC motors with Arduino
There are currently no expansion boards (shields) for the Arduino platform that are designed to do what you're asking of it. At most you'll find shields that can support up to 2 maybe 3 motors. My recommendation for a beginner would be to experiment with a breakout board like this one: https://www.sparkfun.com/products/9457 It's compact and can easily control 2 of the motors you need, three together and you could control up to 6.