Hi garyted51:
Since this is the appraisal forum and you have not disclosed which domain you want appraised (and it is someone elses thread anyway), so you have not met the minimum post necessary for a response in this area of the board. Regardless, if I knew exactly what the FUTURE value of a random 3 letter domain will be and it was above the registration fee, I would have already registered it. Anyone can run one of the available programs and get a list of unregistered 3 letter domains for all TLDs - so it is no secret.
Thus the issue is future value of a domain. I charge $4 US/ hour for predictions. Perhaps you should use
www.Tarot.com which is free and may give better results. Kidding aside, what the value will be in three years is a matter of professional judgment. Some of us professionally judge the new TLDs very optimistically (such as myself), others very pessimistically(such as sellers).
But in general, for sure it is best to simply register good domains such as key-words rather than random three letters.
Good luck