Are you dead set on buying?
If I were you I would go the rental route, you'll save yourself money and avoid being stuck with an outdated piece of hardware in 6 months' time.
Take the money you've saved from your camera budget and put it towards other things that will have a much more substantial impact on your production quality:
- Set design
- Props
- Lights
- Paying a real audio recordist
- post production sound
- etc.
And don't underestimate the cost of feeding everyone!! That can easily hit several hundred dollars for a cast and crew of 7 over a few days.