IF you know what you want, the best thing to do is to call around and ask for a price quote, give them the product # from the manufacturer. After you get a few quotes (ask for them to fax them to you) you can then play them against each other and see who comes in the lowest.

Tips -
ask them to throw in the protection plan for free!
ask for great financing terms
When asking for a low-ball price, don't take up much of their time, do your home work on your own.