Notebooks usually come with a few USB ports and such for you to hook up devices to, but adding a single USB port to Apple's new MacBook will set you back $79.
Apple has done away with the myriad of power, USB, and Thunderbolt ports present on the MacBook air and replaced them with a single USB-C port. While this has allowed the designers at Cupertino to make the new MacBook thinner, it also means that there's only one port for power and connectivity.
That single USB-C port offers support for charging, USB 3.1 Gen 1 (up to 5 Gbps), native DisplayPort 1.2 video output, VGA output and HDMI - as long as you can make it compatible.
And each dongle will set you back $79 each.
UPDATE: Apple has added a USB-C to USB adapter to the lineup of ongles, this one more reasonably priced at $19. However, this does not allow you to charge the device and use a USB device. For that you'll need one of the $79 dongles.
That's a hefty premium for a couple of ports. If you don't need to connect anything to your new MacBook - or charge anything using a USB port - then you can save yourself the money. However, my guess is that a lot of people will find themselves in need of a USB port every once in a while, and that dongle will come in handy.
But it's an expensive dongle, one that costs more than the Apple TV set-top box.