One of the most important issues when raising money from investors is the valuation of the company. This will drive all of the other financial terms of the deal: how many shares will be sold, at what price per share, and how much equity the investor will own in the company after the transaction.
In essence, for early stage (pre-revenue) startups, the company’s valuation is whatever the market deems it to be. I’m not being glib, that’s actually how it works. For example, say that I have a flat screen TV that I want to sell, if someone offers me $800, and then someone else offers me $900. I’m selling it for the $900 and that’s the TV’s market value. If an investor values you at $1M, then that’s your market value. Now he could be undervaluing you, but probably not by a large amount, and if the investment goes forward at that valuation then it’s the de facto market price. Now that doesn’t mean that there is no room to negotiate. That’s why it’s always said that early stage company valuation is an art and not a science.