When I moved here I never expected many things that have happened. I moved from California, a state that is very pro-consumer to Argentina which sometimes appears to be anti-consumer. It was a rude awakening.
All over the world, tourists are usually charged more money to buy things. Many people always say that they want to travel like a "local." The fact is, you are not a local, the second you open your mouth, your clothes, how you act, the locals know that you are not from there.
I remember once in Mexico I was trying to buy something on the beach in Puerto Vallerta. First I chatted up the vendor. Then I asked the price of the item I wanted to buy. He asked me, "Do you want to pay "el precio nacional" o "el precio gringo"? Of course I told him "el precio nacional" which was the price for locals. We haggled and finally I bought. I knew the price, mas o menos, and I knew it was fair.
Flash foward. Buenos Aires is like the last frontier. Anything goes. When I first got here, I ran from store to store comparing prices. What I found was all the stores charge the same price within a few pesos. There was no competition. If you found something you liked you bought it. There were no discounts unless you were paying cash on a large ticket item.
The problem was (and is) the things that don't have prices. It is normal to go into a store and nothing is marked. You have to ask the clerk what the price is. I hate that. Most of the time I don't buy in those kinds of stores.
Once in a fruteria (the stands that sell fruits and vegetables) I was quoted a much higher price for something. In this case the clerk was honest "Porque sos turista". Only I was not a tourist. I told her that, and that I lived here. She didn't care. She called me a name and walked away. I would like to tell you that this behavior is not common, but unfortunately it is.
We have an ex-pat yahoo group. From time to time people post asking for referrals. One man added to his; " I do not want to pay "el impuesto gringo." It was his way of saying he did not want to pay more, just because he is a foreigner.
The other day I was standing in line at the fruteria down the block. My neighbor came and got behind me. We started talking. She told me that she used to go to the fruteria on the other side of the street. "Muy tramposos ellos." she said to me. I was surprised. She is an Argentine. She told me how they would overcharge her. When she would get home she would add up everything and realize it was anywhere from 2 - 10 pesos too much. The day it was 10 pesos she went back, demanded her 10 pesos and said she would never return.
"Wow!" I said to her. "I thought they were overcharging me because I am a foreigner." I told her how they tried that with me. "No," she said, "es mala gente." (Bad people) We both agreed that this place was much better, except for the woman who works there. My neighbor said to me "Una mala persona es una mala persona, es mala con todos." (A bad person is a bad person and they are bad to everyone.)
I agree, however foreigners are easier to cheat. We are an easier mark. For me now, I understand what is going on and I can defend myself. Before no. Every culture has its way of conducting business. Here in Buenos Aires it is buyer beware. Whether you were born here, or just live here.