k9gunner:
Cost is hard to estimate, but expect well over $1000 even going with the absolute cheapest options (which I'm not sure if you want for a S&R team). You will likely have to hire someone to consult/help with this project.
You might want to look into renting space on a trunking system or community repeater before trying to set up your own. If you are in the Dayton area, check out P&R Communications.