Truth be told, the value of a domain can never be told in a hurry. The value of the domain depends a lot on the user.
Research the domain's keywords.
For example: Who are the users of your domain, why buy and how can they afford it? Do research on these. Then set the price.
Domain value checking tools are not 100% accurate. It is nothing more than a comfort to the mind.
However, there are several free popular domain value checking tools.
E.g.
Epik Appraisal
Estibot
Godaddy Appraisal