Best advice is to not do this, or anything like it. If you're a one-man show, then be sure to blog, tweet, or otherwise communicate with your customers often. Treat them like people, and build a following. When your startup fails (and 99% do), hopefully a good portion of those will follow you to your next venture. Building customers through respect is what builds a lasting brand (you). Don't take money until you have a product to give them, unless you're upfront about it.