When I plug in the city closest to where I live in the USA, Seattle ( I live part time in the north and part time in the south) It tells me the prices in my part of the USA are generally 55% LOWER in Buenos Aires, if you dont include rent. If you do, its 67% cheaper in Buenos Aires. And from personal experience, I know many of their quoted USA prices are well below what you pay for organic, or decent quality.
Now, obviously, everybody in the USA has different situations, but a fair amount of metro areas are MORE expensive than Seattle.
Based on personal experience, I know my month to month expenses in Argentia are between 1/3 and 1/2 of what I spend in the USA, and thats not counting the auto expenses I dont have in BA, and various other US specific costs that you could avoid. My health care is only affordable due to Obamacare, which puts my US cost somewhat similar to a good provider in BA like Italiano- but if I lost Obamacare, my healthcare costs would jump to 5 times Argentine levels, plus there would be deductible- my current deductible is something like $2500. Add it all up, and I could, indeed, live like a king in Buenos Aires on what a Union Garbageman makes in Seattle.