Side story on this topic...
My father negotiated for a living, was quite good at it, but he is generally easy to deal with. About 15 years ago, when Craigslist was becoming a thing in North America, I helped him list some quite nice patio furniture online for sale. My mother and he were moving, the furniture was barely used, and he wanted to get rid of it, so we listed it at a throwaway price.
Multiple people reached out, but one individual said they would take it. I marked it sold and arranged to meet at my parents' residence on a Saturday afternoon. At the agreed time, an SUV with a trailer pulls up, clearly there to pick up the furniture. The gentleman then proceeds to offer half of the asking price...
My father looked him dead in the eye and said he would gladly burn the furniture on the lawn right there and then rather than taking any amount less than the asking price, given the value of our collective time.
The gentlemen looked shocked, but the full asking price was then paid, and we assisted in loading the items on the trailer. I've never forgotten that interaction; people can be scummy, but life is tough, and all we can do is act within our principles.