It's also useful to remember that until you have an actual product, the company really does not need a sales person, because there is nothing to sell. A startup does need a lot of things besides a developer, like customer development. But customer development is not the same as straight sales! I have seen some teams flame out because there's a sales person there with nothing to sell feeling useless, and the rest of the team feeling like they are dead weight, and meanwhile real priorities aren't getting dealt with.