[thebean11]

Haggling is the asking for consent part. Are you suggesting that "can I haggle with you?" is somehow more polite than "would you sell it for $x"?

I think it's honestly kind of infantilizing to assume someone who is selling goods for a living is going to be somehow tricked or manipulated into selling at a price they do not want to sell at.

[muzani]

It's not about manipulation, but manners. Where I live, you literally do ask, "Is this the final price?" Or a lengthier way might be, "This is a beautiful thing and I would love to have it! But alas, it is beyond my budget."

Most cultures are not as direct as American. In the US, it's a virtue to save time instead of dancing around the question. But in some cultures, dancing around the question is a mark of respect. You first acknowledge that the seller has been generous and then ask them for further generosity.

[thebean11]

And in some cultures, "would you do it for $x?" is totally normal and expected, including the US in some contexts (like Craigslist or a used car lot).