Plugging direct into the camera is a bad idea. There's no way to adjust levels on the fly as you can with a mixer feeding the camera. If that's what you end up doing be sure the camera is set for mic level & 48v phantom if your mic requires it. Good luck.
If you are are seriously qualified audio person I would pay $350-450. A whole kit would go for roughly $150-175 with 2-3 Lectros with Trams or Countrymans, pole, good mixer, cabling, mics, windscreens, and 2-3 sets of headphones.
If you are a "boom pole holder" this would be maybe $200 (+ $.51/mile if you can get it) and $30-40 for your mic and pole and a single cable. I'd also expect you to hoof gear as needed.
You should find out their camera model and be fully knowledgeable of its requirements and their desired settings. You should also find out exaclty what they are looking for in terms of your services and gear. There are too many mics to show up with 1 and its the wrong one. It's also important for the boom op to work with the LD show you're not a shadow creator.
I was called one time to be 2nd camera as a local stringer. "Just a DVcam, stix and power" is all the assistant on the phone requested know matter how much I asked "we have everything else". When I showed up, they needed lights, a matte box, filters, cables and the DP sent me out as a B unit for 1/2 the day. Long story short, I ended up being a hero because I always bring extra gear and I was able to immediately re-negotiate my rate for my new title (cam op to DP) and get additional rentals above the original contract.
Add value so they call you back. But get educated about the shoot first.