Advice needed: video conferencing tool and camera

I'm looking for a free video conferencing tool for teachers to use for one-to-one conferencing, as an alternative to group meetings and for class to class video conferencing. Any features that mimic WebEx are a bonus.

I'm testing www.tokbox.com now. It's free, browser based and easy to use. Video and audio suffer somewhat but I'd still give it a thumbs up.

As for webcams I'm looking for sub $50 device with decent video and audio. How do you improve audio for group meetings? Better mic?

Thanks as always.