The problem is not the product. The often insurmountable problem is how to get to your potential customers. For example, selling an iOS app or a book on iBook

The problem is not the product. The often insurmountable problem is how to get to your potential customers. For example, selling an iOS app or a book on iBooks is a dead end for most folks. There is just no ready way to get folks attention. The usual method is some social media scheme. Establishing a content marketing scheme or some other kind of social media scheme is the hardest part. It makes getting a product seem easy. I'm not saying don't do it. DO do it, but plan on spending a huge amount of effort developing a marketing scheme. Start thinking about that from the very beginning. In fact, an insight into a workable scheme might be the starting point for choosing a product that would fit the scheme. Good luck!