The first thing you note when you enter a hostel room in Perú is the ample beds. Where are the narrow slabs of thin material that you find in other locations? Perú collectively decided that backpackers need a wide berth to sleep, or engage in other activities. So mattresses are wide, thick, and mostly new. At least until now.
The photo you see is actually a Bread & Breakfast with a couple of hostel rooms. You can see that there are no desks, some shelves to put your stuff, and nothing else. Even if you pay a little more for the private rooms. Maybe you can find those things in the common areas. Every hostel must have some of those. And yes, in some hostels you find multiple ones, very similar to the “living rooms” of South American houses: sofas, coffee table, and a TV. Are Peruvians specialists on traveler interactions? No. Hostels are often built on old houses, with aggregates.
The most important part is the one you don`t note until it is too late: the omnipresent cold. The best months to visit Perú are just the ones when nights are freezing and even damp, from the end of May to the beginning of September. That is why you have those nice beds with massive bedclothes: to cocoon yourself against the subzero Andean weather. Problem is: you need to get of bed sometime. And go to the bathroom. Which is also cold. Calefaction of some kind is unheard of. They just don´t have it. Even if you offer to pay for it. The solution a hostel gave me? One of those grandma plastic bags inside a cotton bag.
And then you have the omnipresent choice: party hostels or quiet hostels? Some of the party hostels, such as Loki Cusco, are full-fledged legendary houses of alcohol-fueled debauchery, so much that they become tourist destinations in their own right, even as part of weekend trips by nationals that will fly from Lima just to get wasted with twenty year old foreigners. If you are twenty-seven or older, and do not look like the poster image of the tall European or American party boy, that is not the place for you though. Just choose a quiet place where you can get to know other tourists at the morning breakfast room. Most of them will not be real travelers, since the Peruvian experience is widely codified for averse-risk young tourists. It takes cheap local public transport and a modicum of interest in the country to escape the one-day tour masses.
So there, Peruvian accommodation for backpackers is affordable, good quality, and pretty varied for your needs. Except if you don´t like the cold at night. Bring pajamas.