One person should press "Generate negotiation ID" and send that ID to the other person. You each enter that ID in the field below on your own device, along with your prices and email address. (Make sure you're both using the same currency.) After you've both pressed "submit", you'll each get an email with the results in a few seconds. In order for both participants to have the correct incentives, you must both commit to abide by that result and not try to negotiate further afterwards.
Are you the buyer or seller?