Ex Godaddy premium domain broker here. Actually the tool prices the domain based on past sales. Godaddy has it's own database of sales that aren't public therefore the estimation is different than estibot. In general, estibot always priced the domains lower than we actually sold them for. Of course, that always depends on how much the buyer is willing to spend and how much the owner is willing to go down. Essentially, let's say you own the domain name MyCar.com. Godaddy will compare "My" "Word" domains that sold in the past with MyCar.com . A great reference is Namebio.com which we used to push buyers to go up on their offer. You can pull up a lot of great comparable sales with it.