Finding a cheap accommodation is also not that difficult.
The best site or app to find cheap accommodation (especially in Europe) is, in my opinion, Booking.com (here with 10% discount). The results can be sorted by price and after choosing an accommodation, you can see the available rooms, the equipment, the regulations of the accommodation, the location (on a map) and reviews from other guests. Since Booking.com is very well-known andmuch used, there are usually a great many reviews, whereby you can more or less estimate the accommodations. Prices shown are for all persons and all nights in total. Especially in Asia, however, we have occasionally experienced that some taxes and tourism levies have to be paid locally. These can be found before the booking at “not inclusive”, but can also be missed quickly, so: give it a careful perusal! Otherwise, bookings through Booking.com are absolutely reliable. Tip: For registered “genius”-members (free of charge!) there are some advantages for the price or check-in and check-out times. If you book through the app or import already transacted bookings into the app, Booking.com is smart enough to store the information of the accommodation (address, telephone number, etc.) offline – which can be very useful in foreign countries. Often there are particularly good offers on the same day as the planned arrival.
Especially for larger groups it’s worth looking on Airbnb (here with a €30 starting credit). There you can rent shared rooms, private rooms and entire “homes” from private persons. The search results can be filtered, but not sorted. In contrast to other hotel bookings, the accommodation request usually has to be confirmed by the host (i.e. a registration with a profile is necessary). An exception are the accommodations indicated by a yellow lightning bolt: these can be booked immediately. The indicated prices are per night, there is a service charge for Airbnb.
trivago scanns and compares a multitude of booking sites (among others Booking.com) but not all types of accommodation/offers are listed. This means that there’s often an even better deal directly on Booking.com. If you have already decided on a specific accommodation, it’s worth doing the comparison through trivago. Prices shown are per room and night.
In Asia, many times agoda has found the cheapest offer. Probably it is simply depending on the region which portal is the most common. Prices shown are per night.