The idea of a "Minimum Viable Product" is a fantastic one.
Instead of wasting a load of time and effort on something that might not work, you build the bare minimum to prove that your product is viable in the marketplace, and then, and only then, do you invest significant time and resources in growing the business.
It's something that's only really possible because of the way we can constantly ship updates to customers using digital technologies - so even if someone gets in right at the start, what they've purchased grows as the product grows.
But how minimum does your MVP have to be?
Is it enough to have a demo? Does it need to be ready for heavy duty use? Should you launch to a small section of the market, just to get feedback? Or aim for a general release?
Personally, I think the answer to this is simple.
It needs to be enough to solve an expensive problem. And no more.
It doesn't have to look great. It doesn't have to be slick.
As long as it solves the problem then people will pay for it, they will give you feedback and you will learn what works and doesn't work. Even if it's dead ugly.
PS: A quick favour - if you know any freelancers or small business owners, I've got a free planner. It helps you decide on the important figures for next few weeks, figure out how much you've got to spend and put a plan in place for the coming month. And it's totally free. So ask your friend to download it here.