On the basis that he's putting in $250k cash at a post money valuation of $750k: What really determines whether this is fair is down to what a 'home run' would

On the basis that he's putting in $250k cash at a post money valuation of $750k: What really determines whether this is fair is down to what a 'home run' would look like. If you are getting some traction towards a possible goal of $xx million a year if all of your ducks line up, then $500k pre money sounds low. But if you're not going for such a big win, $750k post money for a company with that kind of burn rate sounds reasonable to me. Putting $250k cash into a company with no revenues is an incredibly risky thing to do, and he quite possibly well deserves a third of your company for taking that risk. So much of this comes down to market opportunity and how impressive your traction is.