I know alot of factors go into appraising domains. I just want to be able to estimate the value of a domain before I buy. Lets say I'm thinking of purchasing a 2 word .com. I know one factor that would contribute to the value would be the average monthly searches for the keywords. What kind of value would a 2 word (dot com) domain have with a monthly search of 10,000. What about a .net? .info? Would a monthly search of more than 10K pretty much guarantee it will be worth more than the reg fee?
First of all you need to put yourself on the place of a buyer and ask yourself "why would I buy this domain?". Numbers doesn't always guarantee anything. If there is an industry or business sector which is related with that domain it means there might be possible end-users. And "end-users" is the most important keyword in domaining. If there are end-users, domainers will probably take risk and buy that domain if you are marketing it to resellers and looking for a fast sale. Other stuff that are important for a domain are being easy-to-remember, being brandable, search numbers for those keywords, how much advertisement publishing systems are paying for those keywords, pagerank, backlinks, traffic, age, is it infringing a trademark directly or is there anything that you can use as defense in case of a lawsuit etc. You can always try automated appraisal tools like Estibot. But don't forget that those are just automated systems which generally doesn't indicate any correct amount and should be used for the detailed informations they provide about that domain (especially Estibot.) Hope these helps.