No sites are going to give you accurate prices.
The best you can do is use something like namebio.com to see what similar names sold for (I believe GoDaddys valuation tool also shows previously sold names) then see what other similar names are listed for (you won't get 20k for example.org if example.com is listed for 5k).
Google searches and LinkedIn searches might also give you some idea of how popular your keywords are in existing site names. High usage equals high demand equals higher price potential. Maybe your .com is a potential upgrade for someone's .net?
Ultimately the biggest factor should be what would you be happy with.
Either way, pricing and appraisal sites won't give you accurate prices so it's best to use your own smarts and research to determine your own price.