iPhones are ridiculously expensive in India because of the import taxes - a decent chunk of the population would be able to afford them if they were brought in line with the US prices.
https://www.apple.com/in/iphone/
iPhone 13 is listed as ₹69900.00 (920$) vs. $799 in the USA. The former includes taxes, so its only fair to add $80 to the latter (taxes in my state are 10%), so it is still around $40 difference, which isn't bad.
But it appears that the iPhone 13s sold in India today are already being produced in India. If that is the case, any secondary resalers on Amazon are going to take a loss if they imported the phones the hard way (though they could have just smuggled them in).
vs. $829 in the USA
799 includes carrier discounts. You get bank discounts in India which would get the price down to little over $800
iPhone 13 costs about the same as it would if you bought it in the US.
But 13 Pro is a different story It costs $1580 compared to $1099 (incl. tax) in the US. I guess they don't make iPhone 13 Pros in India