You can do it!
Camera w/ Mic + Light
This is an inexpensive starter camera that includes a mic. Add a light and you're good to go.
Mic + adapter + headphones + stand
If you go this route, make it a second iphone, use your old one! You need an external mic, adapter, headphones and something to hold it.
Lights, Audio, Tripod
I like using a wireless lav microphone and a monopod, for decent audio and some stability.