how can i evaluate my non top level domain that has no content on it?

[Firs]

i do have a 5 letter brandable domain since 2002. I never used it so i think its only value is that it is 5 letters 11 years old and never been used to any illegal thing. However it is not top level so i dont know if it would worth a thing. Where can i evaluate the domain itself with no content on it?

[Jake]

I don't understand what non top level means.

A TLD would be cars.com

A subdomain example would be cars.blogspot.com that's one example of a non TLD.
strictly speaking Google owns that name, I believe their rules prohibit reselling one of their free site domain names.

If you really do have a regular domain name, you might look through the prices on the Godaddy.com auction you can set filtering to only show 5 character names. Whether a sensible word can be made from a domain name is a big factor. m2521.com would not be valuable.

I believe they offer free appraisals at namepros.com

[Jesus]

If you attempt to list it on GoDaddy Auctions, they will evaluate its worth there!