Well worth a debate. I remember my outrage when I first realised that Peruvians get cheaper flights and entrance to Machu Picchu etc but this quote sums it up rather well: “Travel is not a right, it’s a privilege”.
Understanding communication and knowing what you should be paying are integral to not getting ripped off on the smaller scale, however the fact of the matter is that the majority of places that charge more for foreigners are third world and you should see it as helping development. It's our privilege to be able to travel to places where those people might never be in a position to see another part of the world.
These are just the tip of the iceberg too, so many hidden gems in Peru. Enjoy your trip!