If you have been doing these jobs for a while you should be able to have an initial client meeting and throw out some ball park numbers based on what they are looking for. If you can't or don't it might be worth your time creating a document that you have designed and priced out with various levels of systems so that you can throw a number out in an initial meeting. If the client then wants to move forward you sign a design agreement and collect a small deposit and start the design and proposal package process.