Assuming measurements off of prints; Measure all surfaces and get the sq/ft total. You will need to know what type of finishes are specified. Go to your local paint store, with the measurements and prints in hand, talk to your sales rep. Your rep will know the current going prices to charge. If this price is too low bump it up to meet your needs.
Also while measuring, think about time and material costs. As mentioned, this is the best way to get at a price that you can work with.