If you have a laptop, tablet or smartphone this will have a built-in mic and webcam and you should be pretty much good to go. We would recommend a headset or ear buds for any situations where there may be background noise.
If using a desktop PC, or if you find your built-in laptop equipment insufficient you will need to purchase a headset with a mic (and potentially a webcam). We recommend the following based on our experience:
Logitech C920 HD Pro Webcam
Logitech C930e Business Webcam (Recommended option)
Good basic model.
Very good model. Similar to the above option but with comfier ear-pads and a volume control/mute button on the cable.
Logitech H570e or H650e (Recommended option)
Both excellent headsets, highly recommended. Come in stereo (two earpieces) or mono (one earpiece), some prefer mono as it leaves one ear free to hear what is going on around you but stereo maybe better for full attention. Also has controls on the cable.
MXL AC-400 USB Gooseneck Conference Microphone
Excellent option for individuals. Has mute button to easily mute and unmute yourself.
MXL AC-404 USB-Powered Microphone
Very good for individuals who prefer not to wear a headset or small groups up to approx. 6 people