Audio is the most important aspect of the lesson experience, because it allows students to hear your accent, pronunciation, and what you're trying to teach.
Here are some great choices we recommend:
1. Logitech ClearChat Comfort/USB Headset H390 (Black) (Low Price)
2. Logitech Desktop Microphone (Medium Price)
3. Etekcity RoverBeats Bravo Professional Over Ear Stereo Headset with Microphone (Low Price)