Well, I can't say much about low budget, as my wife has recently purchased a professional HD movie camera, and Liquid editing software, which I believe is the standard for most tv shows nowadays, however, for what she got, she paid less than 6000 Australian dollars.
I used to use my Fuji 6.5mp still camera in video mode, recording 640x480, and just trusted the inbuilt microphone, which did a pretty reasonable quality recording.
When Miranda bought her camera though, I found I needed a seperate audio track, so I hunted down a professional quality recording microphone (Samson CU30 USB mic - 200 dollars from e - b a y) which came with great recording software (Cakewalk)... Highly recommended! I've never sounded so good!
The videos that we now produce are HD and great quality, but a little too large for this forum, so we use Youtube as a vehicle for them.
15 years ago we would have been talking in the hundreds of thousands for this quality.
I love technology!