This backpack-friendly speaker uses Bluetooth technology to wirelessly pump out music from connected phones, laptops, and MP3 players. Thanks to its built-in microphone, it pulls double duty as a speakerphone as well. And it’s available for just $39.99 right now on Groupon. It’s normal price is $129.99, which makes this a steal. It’s also available in red, blue, white and black. You can grab it from the link below.