I see, I liked to buy from eBay and Amazon, but they added sanctions and the only way is to use an Iranian website which does the middleman's work and it takes more money and also it might takes longer time to receive your stuff, so it is hard to buy from those websites, I think this is how our inside online markets started their business, like instead of Amazon, we have Digikala. I will check the other platforms you mentioned just to learn more about them.
I didn't know about haggling in car dealerships, so there is something similar, interesting :).