Im guessing your new at this game right?.
If you are you could save alot of dollars and trouble by reading the appraisal section and checking out recent sales.
Just remember that when or if you do check out recent sales data, many of the domains sold at high prices, some that even dont make any sense, has most likely been sold to endusers.
My point is that if you see a domain name like "435sales.com" sold for $3000, then you shouldent go ahead and register "425sales.com" , simply because there would most likely never be anyone interested in it. The guys who baught 435sales has probably already started advertising the name, or they have a plan setup for it. If not they wouldent have baught it for that price and they would go ahead and register another number.
We have all been there, most of us anyway, registering names without value, but the good thing is that we all learn =).
Cheers,
Andree