Another way to think about it: let $x be the salary you could earn elsewhere, and N be the number of years you'd wind up working for free. It doesn't matter who

Another way to think about it: let $x be the salary you could earn elsewhere, and N be the number of years you'd wind up working for free. It doesn't matter who you are, $Nx is a pretty substantial amount of money. You're basically being asked to pay $Nx for 2% of a company at the "two guys and an idea" stage. That doesn't sound like much of a deal. If I were an angel investor I'd be wanting a much more substantial stake in the company for that kind of money. Even YC usually winds up with at least three times that, and they generally put in a lot less than whatever $Nx is.