You probably should have just searched for Online Hobby Stores on these forums and you would have found lots of answers.
www.walthers.com is the cornucopia of hobby stores. Of course, even their sale prices tend to be high, but their selection and customer service is unequalled, anywhere.
I have had good luck with the both Dallasmodelworks.com and modeltrainstuff.com (AKA MB Klein), and I think you'll find them highly rated here as well. While I have never had trouble with them, Blue Ridge Hobbies (www.blueridgehobbies.com) has some less than satisfied customers here, and their customer service is, well, spotty.
Internettrains.com is, as stated above, a clip joint. Caveat Emptor.
May, I, however, suggest that you investigate a LHS (Local Hobby Shop, to the newcomer) option. Their knowledge and experience is usally unbeatable, and it's good to support the local business (and you'll generally pay less in sales tax than you do in shipping).