It all depends on what the buyers sees in the domain.
A 3 character domain may have particular meaning to a particular
Many 3 character.coms sell between $15-$75.
Recently "45s.net" sold for $60.
I have received offers of $35 for XL9.com
Note: as they become less available, they become more valuable,
and they make for nice email addresses
Easy to remember and less chance for misspelling.
Wise investments for the future!