Curious that we have a convention that we haggle on buying cars and houses, the two most expensive things one ever has (apart from a daughter; right, dads?). We don't, in Britain, do it with anything else, with the possible exception of antiques.
I do a deal on anything when possible. I used not to on hotels, but my ex taught me how to, turning up with no booking, late in the day, never expecting 5* to reduce price (they have an image to keep, but will always give upgrades and free meals; find trivial complaints about every room until they give you a suite for the price of a small room) The other grades just reduce price; late in the day, if they still have rooms, what chance have they of of a booking at all, apart from yours?