I suspect most YouTube video is done using the mic built into the camera. As soon as you start recording sound separately you've a big investment in time and money getting the sound and video re-united.

If your webcam doesn't do sound, get a real digital camera that does video and has a USB connector (most do and have), a decent sized memory card for the camera, and experiment extensively for best camera position for good picture and sound.

On a tight budget, and with advantages of its own, get a friend with a suitable digital camera to do the shooting for you.

Interms of your own suggestions, you could get a cheap external mic that designed for use with computers. Again experiment carefully with mic placement.

Yes you can get two mics and a mixer, but frankly the money's wasted for YouTube quality.

Anahata

Anahata