From whom I quote:
"After nine prototypes Martin Aircraft have an accurate expectation for how much a jetpack will cost, and suggest that at $86,000 it is pitched at the level of a high-end car. As sales and production volume increase they expect this to drop to the price of a mid-range car. A 10% deposit buys you a production slot for 12 months hence; progress payments are made during manufacture with final payment due on delivery. Details and a deposit contract are available from their Martin Aircraft's website."
I don't actually see the details/deposit contract on the website. What the website does say is:
"It is expected that early orders for sales to private individuals will commence late 2010. If you would like to register your interest in purchasing a Jetpack for private use, please do so through our contact page. We will note your details and contact you..."