Love "The Mom Book" and the whole Lean Startup approach.
However, there is one bureaucratic problem. It's not easy to do presale. Not sure how it works in the US, but in Ukraine, where my bank is, it freaking hard to accept payments online.
I have to go through a whole bunch of verification processes to start accepting payments on my website or app. And the verification is done by an internet acquiring service provider as well as Master Card. The first one is not interested in startups with next to no revenue, the latter one is not interested in anything that the reviewer doesn't understand. For instance, the guy who reviewed my last project was unable to comprehend what is "Browser extension".
How can I do presale? At this point, I don't care about service fees much. I just want to validate my idea by accepting prepayments from people who tell me that they want to buy my product.
I have 2 means of accepting legal payments from abroad companies: Payoneer and SWIFT transfer. Payment amounts vary from $10 to $200 depending on the project. And since it's a presale, I need an easy refund option.