1) Determine a fair price 2) If they insist on being AS ridiculous like cutting off YOUR API access... - Prepare a Twitter / Blog campaign (#zillowfail) - Get the NYtimes reporter aware of this. They will listen to you if your email subject is "Unethical, unfair behavior from Zillow" 3) Negotiate further.
The HN hacker/Twitter community will help out. This is ridiculous
Determine a fair value for your work and negotiate. It's a shame they opened with a low-ball offer backed by a threat (if this is truly how this all unfolded), but be the bigger man here and forge some cooperation! Maybe then they can learn a lesson about dealing with API devs without first seeing them scared off by a personal vendetta campaign
That term has no definition.
Instead "determine a price that you can live with and they would rather pay than go with their second best plan".