Don't take it so literally. Can you find 100 people (or a few dozen) in your circles that could be first users of your product? Start with them. If you have trouble gaining traction with those folks, you may have trouble getting others to pay for your product.

The caveat being that you have to make sure the people you're inviting fit somewhere in your customer profile. You can get discouraging feedback if your initial invitees don't fit your product.