Issue with Startup Valuation 
jacquesm: Without further information (such as the size of your average sale, the potential market for the product ('killer' is not enough), the time invested and so on) it is very hard to put any kind of value on what you have there.My suggestion would be that you approach a professional in the field (for instance a friendly VC contact) and give them the figures as much as you can and then work out a reasonable bandwidth together.This will take you some effort, but at the end of that you will know a lot more about your company than you do now.Make sure that you do not end up paying Mr. X his own investment back as a salary, otherwise he's just an equity-for-work employee, not an investor per-se.