Basic Gear for Digital Filmmaking.
If you're really lucky you'll find some great people to work with who have their own equipment, especially a videographer, sound recordist, editor, etc. but if you want to be a guerrilla filmmaker and put together your own equipment package, you'll have to raise a bit of money.
Camera
People are shooting video on anything from phones to point-n-shoots, handicams to prosumer video cameras and on up to higher end pro cameras depending on their budget. What you shoot with is often less important than the creative vision behind the lens. The best camera in the world can't improve a bad script or bad acting.
If you're shooting with a smaller camcorder you can find ideas for accessories here
The current trend in video filkmmaking is shooting HD video on a D-SLR like the Canon 5D or 7D. You can check out a sampling of gear that's available for video shooting on these cameras here
Panasonic has released their first video camera that shoots DSLR video with the option to change lenses, the Panasonic AF100.
A lower cost option is the Sony NEX-VG20, a combi-cam that merges the auto features of a handycam with a DSLR sensor and changeable lenses.
Canon has a more traditional camcorder called the XA10 which shoots AVCHD to SD cards and includes an XLR audio adapter. The Panasonic HCX-900M is a handycam which packs a lot of punch for a small camera with 3MOS Chip - 3 x 1/4" Sensors, 32GB built-in memory/Recording AVCHD to SD cards/Full-HD 1920 x 1080, 60 progressive recording.
Find a variety of HD camcorder in different price ranges here
Dependng on the size and type of camera you're using there are a number of options starting as low as $25 for a simple grip handle and up to $600 for shoulder rigs. You can also find table dollies, cranes and camera sliders priced according to how elaborate the rig is and the weight of camera it can support. For more traditional shooting especially for interviews you should invest in a good tripod or monopod for situations where a tripod is not practical.
Portable LCD Field Monitor
This is especially useful if you want to shoot video on a DSLR.
For professional sound recording you may need different mics for different situations.
Rode makes an excellent XLR shotgun mic, the NTG2 . If you're shooting with a camera that has a mini-jack input you can use a shotgun mic such as the Rode VideoMic or VideoMic Pro which connects via minijack instead of XLR. If you want to use an XLR mic with a camera which only has a minijack input for audio, you'll need an XLR to minijack cable or an adapter by Beachtek. One advantge to using an XLR shotgun mic is it allows you to use a boom pole more easily since XLR cables lock in preventing the mic cable from coming unplugged during recording.
You can also use wired lav mics or wireless lav mics for recording.
Another option for sound recording that is popular with DSLR filmmakers is a digital recorder like the Zoom H1.
Find more audio accessories here.
For lighting you can use a portable studio lighting kit that can be easily transported and assembled on site. Westcott has some well-priced two light kits that come in tungsten or fluorescent with softboxes and stands. You can also put a light on top of your camera for mobility in situations where you do not neet to light a large area but just brighten the shot for close up interviews.
Lighting kits and accessories
On-camera lights
See a full range of video accessories here