[SkyMarshal]

Read Fischer & Ury's Getting to Yes if you have time. Great little book on negotiating. One of their main pieces of advice is, before entering any negotiation, work out your BATNA - Best Alternative to a Negotiated Agreement.

A BATNA is not the lowest price you're willing to accept in a negotiation, but rather what you would do if the negotiation never occurred in the first place. Bootstrap your product, try to gain traction, profit? Raise angel/VC money, work towards an exit strategy? Apply to YC?

Once you have that figured out, you can enter into a negotiation with a much better idea of the value of your product to you. If there is overlap with that and what the other company is willing to offer for it, then you can make a win/win deal.

It also helps to have some idea of the value of your product to the other company, as you do.

Good luck, and congrats.