As you say, this practice has already become quite common in society. I would say it depends on the person, sometimes I seek to lower or negotiate the price slightly, because I really can't afford it at the moment and the truth is I've been interested. The difference is minimal. Although what you're saying is very true, they're usually low-income salespeople who earn their daily bread from these purchases, so we shouldn't overdo it if we can spend a lot more on other things!
However, we can see the other side of the coin, when they make us a special offer at a low price and tempt us to accept. That would be more acceptable.