I have to agree with JP and not JG on this one. JG went off subject here, but in things related to travel-tourism, I have even seen discounts for locals in the USA. For instance, if you live within certain areas you can get cheaper monthly passes for the toll roads, bridges and tunnels, and ferries. As a tourist you would not benefit from these unless residing within those areas for certain times, but you may even need to show some local ID, such as a US driver´s license, or proof of your residence.
Argentina has a very devalued currency, so much so, that we usually find it virtually impossible to travel abroad. Look at Europe now. It´s 5 to 12 times more expensive for the same items there than here. So if we can get a break inside here, that seems logical. You should consider any difference as a DISCOUNT for locals.
Now, this should NOT include purchase of goods at stores. (NEVER pay dollars, all prices are supposed to be in pesos unless clearly marked as USD). To the contrary, tourists can actually benefit from a LOWER PRICE by getting a refund of the 21% IVA tax, (value added tax), if you do the paperwork when you leave the country, same as tourists in the US. (You can see this at the info desk at Galeria Pacifico.)