car sharing/providing shuttle app locally.

I want to create an iphone/android app that will allow subscribers (car owners and would be renters) to rent their own vehicles for a fee on an hourly basis. The app will connect both owners and renters locally. For instance, if someone has a car they they are willing to rent for 2 hours today. By logging in on the app, that person should be able to post the availability of their vehicle and for what price. The would be renter would also have to log on and search for what is available within their area. This should show a map of how many car owners are available. Very similar to pin drop placed on Google map. Clicking on the pin drop will show users the owners information as well as their vehicle info and rental price. In addition, the car owners can also have an option of providing shuttle services if the renters want to get a lift from point A to point B. This app will serve as a connection between these end users. I'm not interested in providing any services. The app will be free to subscribers but can be included with ads. The app should also allow users to rate each other about their experiences and provide a way to collect personal info for background checks. It would also link subscribers' accounts to Paypal services or online payment. AT this point I need to know the cost of creating such app and any additional fees for maintaining the app once it is up and running. Thanks.