Zero to -$50.00. IMO.
You're looking at negative value depending on what your time is worth. I like to think of my time as worth $100/Hr since that's what I charge when I go onsite. Therefore if I were to take 30 minutes to register 2 worthless domains, they would be worth -$50.00.
In the future, avoid registering names that don't end with .COM, .ORG, or .TV. Good luck and may the force be with you! (: