That's essentially what Kickstarter is. You get backed before you build your product, and you don't even need to convince people it exists because they expect y

That's essentially what Kickstarter is. You get backed before you build your product, and you don't even need to convince people it exists because they expect your product not to be finished. I think it's an excellent model as long as you live up to your promise and deliver above and beyond expectations. It's how I started my software developer course selling business and validated the idea (spending hundreds of hours making a course is no different than a SAAS MVP). I wrote all about this process recently in an Indie Hackers interview: https://www.indiehackers.com/businesses/nick-janetakis https://www.indiehackers.com/businesses/nick-janetakis.