For a few projects I needed to get better sound out of the videos I'm creating with my HDSLR (a Nikon D3100) cheaply and in a way that wouldn't require me to use a second person when shooting.
One option is to use a wireless lavaliere, but the D3100 doesn't have a audio input.
After thinking through this for a while, I realized that I could record the audio separately and sync it up later. I bought the Zoom H1 for $100 and a decent lavaliere condenser mic for $20. This is my test, with the mic and without.
One nice thing about the Zoom H1 is that you could also potentially mount it to your camera for less "directed" video.
Zoom H1 - amzn.com/B003QKBVYK
Audio Technica ATR-3350 Lavalier Omnidirectional Condenser Microphone - amzn.com/B002HJ9PTO
Nikon D3100 - amzn.com/B003ZYF3LO