Walking away from a deal you do not feel comfortable with is always the right thing to do no matter what you are buying. If in a couple of days you find it was a sweet deal, you can always go back.
I make it clear when I am dealing with any product; what it is I want, including options and that the number they give me includes taxes, fees etc.
I tell them upfront that the number we agree upon is the number I write on the check; anything else come out of their pocket and I only have one check.
It cuts though a lot of BS right away.