1. Daily Rates vary but $450-$550 per day is common for the 200/300. (Google the pilot contract pay rates.)
2. If you're qualified as Captain/PIC, you need to be paid as such. It does not matter if they use you in that capacity. Remember: You'll need to pay for your own recurrent, etc.
I flew Part 135 in the Daytona Beach area in 2002-2004. We had a C90, B100 and B200. I was PIC and occasionally flew SIC. I was salaried at $55K/yr. However, the company paid for training, RGS, Medicals, and I had health insurance.