Bargaining within reason is fine Janie, insulting a seller, as gnu describes hus experience, seems in the area of being rude to me. If you want to try extreme bargaining,   try doing a "low ball" online and you may find you get a rude response.

The thread brings to mind a yard sale experience:

A few years ago I participated in a street yard sale. One item I put out was a low quality pirtible CD player for 50 cents. A young Asian guy asked me jf he could hear it working, I said sure and spent a considerable time hooking it up and finding a CD to play-results, it clearly worked. He asked me a few technical questions about the player, which I coukd not answer. He then said, I am really looking for a high quality player. Frustrated by wasted time, I could not help by responding "well, maybe you should be looking at other locations, rather than yard sales and select sets with prices somewhat higher than 50 cents. His puzzled lookvseemed to indicate that my comments went completely over his head.