Let's say someone orders some take away food by phone and are told that the bill will come to say $70.00.
They've already made the food (and again, told the price beforehand) thus would it be seen as unethical (even bullying) to haggle when picking up? Maybe you could say… 'how about' or 'would you' take $50.00 or some such discount as just one example. In many cases you'd have the upper hand as they've taken the time and made your selected order.
How might you expect a small restaurant or food service/take away to respond to this and would you see someone asking as rude, cheap or even bullying? Using more the example of the smaller establishment and not a huge chain such as Maccas' or KFC as of course systems will automatically disallow such.