Its good that flippa give one free listing for every 15 domain names that you appraises. It will take just 5-10 minutes to do that.You saved $9.But are there any serious domain appraisers?I highly doubt that.Most of the appraisers are new members just trying to get that one free listing.Once i submitted my domain for appraisal and the result is just so fake. All the appraisals are new members. Most of the comments are like" Great domain,nice keyword easy to remember,put it into auction" And the figure reached upto $$$$$.
So here's the deal... The value of a domain is the whatever someone is willing to pay for it. 98% of the time any domain I see for sale is ONLY worth the registration fee *IF* you want it. Odds are if you are looking for an appraisal service for your domains you don't have anything of value. Seriously..you would know if the domain you have is something someone would want.