Haggling vs bargaining, some thoughts
Haggling and bargaining, in are words used to determine the exchange value of a of an object or service. Not all people value things equally. but then you knew that! And again my own perspective is that it would be a much less interesting world if they did, and certainly there would be alot less variety.
Haggling, holds an often deserved stigma of pettiness and pushy or dominating behavior. People who might being described as unreasonable, heavy handed, wanting something for nothing ,or threatening are images the word haggling could conjure. The product is often offered or requested for a much reduced price.
Whereas bargaining is a more genteel word, or image. It implies a friendly or even respectful manor. Participants "remain calm, cool and collected", a negotiation for something of equal or even higher value, at times that might be a concession.
The essential part of these exchanges are not how valuable a particular service or object is, it is how valuable it is to those who are engaged in the bargaining and/or haggling.