The term "bargain" is used in Contract Law to define an agreement between two parties. I pay you $5, you sell me your old hat. We have a bargain. To most "consumers" the term "bargain" implies some sort of discount or sale or freebie. I am not using the term in that manner, anywhere in this blog, unless I describe something as a "good bargain" or "bad bargain." A "bargain" by itself is value-neutral.
If you can set the terms of a debate, you can win the debate. And we see this all the time in politics. Abortion opponents are not "anti-abortion" but "Pro-Life!" - and their opponents have similarly named themselves "Pro Choice!" - a naming battle the pro-abortion side clearly lost ("Life", in terms of emotional index, beats out "Choice" every time).
None of this happens by accident. Merchandisers, advertisers, and marketing people know how we think emotionally and how to get to us, often in very subtle ways. And one of these ways is to redefine the very language we speak.