I'm an INTJ. Us INTJs are notorious for being impossible to influence by sales people or anybody else.

If I'm in a store shopping, I make my own decisions based on my needs, budget, and knowledge on the product at hand. I am rigid on how I make my selections. Anybody who has ever known me well enough knows to leave me the hell alone when I'm trying to make a decision.

If a sales person comes up to me and doesn't get the hint that I'm not interested in what he/she has to say, I will shop elsewhere.