To the naysayers in this thread: You have several options here other than just saying 'oohhh, this is mean and nasty'. - match the offer with a better one, so all those that would take up the OP would flock to you instead - build your MVP, keep 100% and then do your own marketing. $5000 for 50% difference but you get to do all the work. Either one of those would be so much more effective than just berating the OP or…
Exactly. This is great, out-of-the box thinking by the OP. Anyone who want to do something like this (esp. the OP and jacquesm), please connect with me on LinkedIn: Terrence C. Yang, mentor, angel.
I'm tempted to make a similar counter-offer as a developer. Do some customer development, prove the market, and I'll fund your product development and build it for you.