Need to know cost details of android app development services

I want to take the best android application development services in Perth, but I am not sure how much does the services cost, and I need some serious help in making the budget for availing the services from a professional android app development company in Perth. I have all the plans and ideas ready for the application that I need to discuss with the professional developer to develop as soon as possible. It will be so helpful and convenient for me if anyone could guide me with the pricing so that I can set the budget right away before contacting them.