[futhey]

I've done a few of these. Basically, you need to quote them significantly more than you're currently comfortable asking, because it's basically going to suck up months of your time and you're going to have to re-tool your business to meet their requirements. Let's say $10k-$20k, assuming from your numbers they're 100x the size of a typical customer.

Quote them such a large amount that you expect them to say no, and then make your peace with them saying no. Don't accept a significant discount on what you quote them. Instead, let them go, and wait for another enterprise customer to come along.

Do a call to understand why they want to buy your product ("I wanted to know what you were having trouble with and how you think our product could help") and come up with requirements up front. Charge extra for things like enterprise sign-on if they haven't been built yet.

This customer could make or break your business. If you quote is too low you risk regretting the deal not only on your end, but the potential that your enterprise customer backs out as well when you inevitably hit some stumbling blocks.

Your first enterprise customer is like winning the lottery – it's okay to play, but don't bet everything on winning. Expect to lose, and set yourself up for a big payoff if you end up making it work. Plan to learn from your mistakes either way.