A few people at a forum online recommended this super cheap mic for filming. The model is called iSK CM-20C Super-Cardioid Condenser Microphone. It cost $27 plus $18 shipping from Australia to America at ebay.
I believe most people do not know anything about this brand. I thought it is so inexpensive, so it does not hurt to give it a try.
I am far from sound expert. I do not have any expensive mic that I can compare to. So just listen to it yourself. If you think it sounds good, then you perhaps can give it a try too.
I used it for a promotional video recently. It was filmed indoor, so pay attention to how it perform indoor.
The mic connectted to the juicedlink rm333 preamp, and the sounds goes directly to my Panasonic GH3 camera.
Here is the sample video.