This place is great - food is excellent, service is wonderful, and the price is the best of the vegetarian places we've been to in Arequipa. It's 7 soles for the menu at lunch, which includes salad, soup, main, drink and dessert. They also give you a yogurt unless you tell them you can't have dairy. The salad on the day we went had cheese, but they made a plate of sliced cucumbers, tomatoes and olives instead when I said we couldn't have dairy.
They're also open for dinner, which is good since most of the other vegetarian places aren't, but they don't have the same set menu available, you basically order a la carte although you can add a soup to your main for very little.
Cons: not everything's vegan