John, I think you have all levels of people responding here. Some with decades of experience in the business, some with far less. From my standpoint, there is a catch 22 that exists in the beginning. Only a moron would give someone they don't know cash up front for a job, if that person couldn't provide one hell of a portfolio of high quality work that would make the customer feel extremely confident they were going to get a high quality job. So who gives money up front to someone with no killer portfolio? Morons or very trusting people.
As you build that portfolio, it allows you to be in the drivers seat at the meeting. It allows you to showcase your work, which makes them feel comfortable and like they are dealing with a real professional that knows his/her craft. They'll hand you their money, no real issues.
So you're stuck. You don't have the portfolio, but you want the money. Your work may very well be worth it, but you have to figure out a way to work through it until you do have the portfolio to justify your requests. In my experience, when you are new, with a limited portfolio, YOU have to take some risks, not your CUSTOMERS.
You are trying to built a relationship, that's what customers are, relationships, not flash in the pan, here today, gone tomorrow people. What can YOU do to make him feel more comfortable with the transaction?
Yes, it's on you, not on him. As a side note, if you treated me that way, I'd have walked and you'd not have had that return call from me. I'd be at your competitors getting my pricing info.