I bought this cheap, simple movie rig from eBay. It's widely available and averages around US$70.
Anyway, after spending some time with it, I can say that it's a good buy. It's cheap and makes you mobile (compared to using a tripod). It can be configured in many ways but to minimize shaky videos, it's best to use shoulder mount configuration.
Depending on shoot environment, I have now the choice to use a tripod, monopod, or this simple rig. No more handheld shots, D800+lens is way too heavy ;-)
For a quick comparison, click HERE.