The only way to know for sure whether you are getting a good deal or not is to do extensive research. Shop around, shop around again, then again. If you register interest in a dealer and a specific type of car then eventually (if he does his job right) he should end up chasing you, desperate for your business.
Don't forget to compare apples with apples or your shopping around will all be in vain.
Good luck playing hard to get with all those used car dealers....
Check values in the private sales market too, see if you can get yourself a cheaper car this way...
JJ
You gotta tie yourself to the mast my friend, and the storm will end.