My experience in Argentina regarding spanish has been pretty good overall. With all the "english teachers" both Argentine and Expat, it's not hard to find an english speaking person in a crowd. The problem is NOT speaking spanish and learning.
About getting ripped off.... Yes, this does happen. Just like it would happen anywhere that people have an advantage over you. Is it bad in Argentina? Not really. There ARE tourist prices though and that's not even a secret. More like an accepted policy. If you're from South America you pay 10 pesos to get into the national park at Valdes Peninsula while foreign people are charged 30. It's the same thing at the Glaciers outside El Calafate and even places within BA, although that's not a "posted" price difference like major tourist sites. Locals simply don't pay when they walk into a club while you nailed for 20 or 30 pesos.
Something else I noticed especially down the coast of Argentina is the "discount" offered to holders of DNI id's. With my limited spanish, I could figure out on the sign outside an all you can eat buffet place that if you could produce a DNI then you basically got a 2 for 1 deal. I asked Argentines about this practice and they say it's becoming common as inflation kicks in. I suspect it happens with Bus tickets and KNOW it happens with airline tickets.
Back to the subject of spanish (or lack of).... I actually did a few tests on this when buying cigarettes. Half the time I would walk up to a Kiosco window and just hold up an empty pack and say "uno mas" or something basic in spanish but just enough to get the point across. I also dressed like an Argentine guy, as in I didn't shave and wore a football shirt. 90% of the time I was charged exactly the same for the same brand and pack of cigarettes.
The other half of the time, I would speak english with broken spanish plus act confused, like this was my first time buying cigarettes in Argentina. "Give me that red pack there" pointing at what I want. Then I'd ask how much and hold out WAY too much money. 70% of the time, they still charged me the correct price. 20% it was 1 peso more. 10% it was at least double. 6 pesos for a 3 peso pack of cigarettes. A box of matches was where they really nailed me, since that ranged from 20 cents to 1 peso. I've since quit smoking by the way.
Sometimes the ripoffs backfire. While I was in Bariloche, I walked into a sandwhich shop and looked at the menu built into the counter. I asked for a couple things to eat and after the lady put them on a plate I asked for a mini bottle of coke that they had on display. Before she opened it I asked how much it cost since there wasn't a price anywhere. She said it was $2.50. I said she should put it back. Another woman customer in the cafe was watching all of this and smirked when I caught the price shift.
I sat down at the opposite counter on a stool and ate my food. A minute later, a couple strolled in and the woman asks how much the mini bottles of coke are. The woman behind the counter sees both myself and this other customer watching her and she says $2.50. The tourist customer flips out saying that this is too much and where she comes from it would cost 75 cents or $1.50 at most!!
At this point, a man comes out from the back and asks whats going on. The customer woman complains again that she can buy it for less somewhere else and the owner guy goes into damage control. He tells the customer that it only cost 1.25 for the coke and tells that to the counter woman. Everyone is happy again and the couple get their drinks and leave. I finish my sandwich and take my empty plate to the counter. The counter woman gives me a frown and I say (in spanish) "Thank you very much. God is watching you". The other customer in the cafe giggles as I walk out the door to the kiosco next door where I buy a mini-coke for 1 peso.
