Thanks a lot davismfl for taking time to write detailed and useful advice. If its not a secret I would love to hear more about the product you sold in 10 days to a fortune 100 firm.
What happened for us to sell it to this enterprise was we found out they (a large public firm) were trying to hold a conference but had been struggling to glue systems together themselves to make it work and advertise it etc (they disliked other in market products). We heard this as a pure rumor from some engineers that were bitching about it at a meetup we went to on mobile development. From there we researched the company, the conference and started cold emailing/calling the people who were responsible for the conference at the company. We were able to meet with them within a couple of days, did a few demo's and showed them it wasn't vapor and really existed (seems to always be an enterprises concern). Like all small companies, we had the normal "call for pricing" for "enterprise" clients (though we hadn't really had anyone this size), so pricing was on the fly customized for them. We screwed up a little on pricing because I bet they would've been happy to pay double the price and still feel they got a good value which would've given us a better margin.
In the end, no regrets just a good lesson for the team (me included) that pricing is relative to the client and while you should never rape a client you do need to make sure the clients expectations and your pricing are in line. In our case we made a profit, but it wasn't as much as even a standard client simply because of all the extra support we had to do, hence we should've asked for more. Enterprise clients are super needy and they know it so pricing it like they are is critical. Funny part is we came up with a price, then doubled it (thinking they would be needy) which also made them feel good about it (too cheap and enterprise clients will back away knowing you can't handle them), but we should've triple or quadrupled it to make better margins.