The difference is that the dollar value of time in America is higher. So while an Indian may haggle over a bag of lemons because the rupee value of the lemons vs. time is what it is, the American won't.

You'll often see this when selling used stuff in America. Poor people will haggle to the end of time because every dollar matters to them - something that manifests in selling something at a higher price being more risk-free than selling something at a lower price. For the same reason, if anything goes wrong with the used product they will be upset with you. Because every dollar counts to them.

I throw away cheap stuff instead of Craigslisting it because of the danger of it only being worth buying to poor people.

By the way, Americans prefer calling it 'negotiating'. You 'negotiate' a lower price, you don't haggle things down to a lower price.

Haggling is acceptable in Canada/USA with most large purchases. Cars, houses, hand-made furniture, bulk purchases, building leases, etc. Haggling is generally not accepted only when it doesn't scale well, which also has the advantage of greater transparency and fairness in those cases.

In line with the above, private sellers are generally amenable to haggling because it doesn't matter that it doesn't scale. So when buying a used anything on Kijiji, haggling is expected, particularly if it says "OBO" (or best offer), but not if it says "firm".

If the price is set semi-arbitrarily at the time of purchase, like some U-pick auto junkyards, the person setting the price is right there anyway, so haggling may be acceptable.

I haven't researched any of this; this is just my intuition from experience.

This matches my experience; I think some Kijiji sellers do get haggling fatigue after a while, where they've dealt with one too many tire-kicker types who show up offering 50% (or less) of the listed price. Or play other games, like agreeing on a price and then showing up short of cash and making a scene about having to drive back out and find the nearest bank machine. I had this happen once and stood my ground over it; suddenly the missing $20 miraculously appeared with no ATM trip necessary.

Anyway, being able to advertise a price as firm does provide a convenient escape hatch in that scenario.