It's not actually as obvious as it sounds. It's not enough to just look for a cheap hotel – there are several other options.
Hostels. If you're someone who doesn't care how many pillows there are or what the bathroom looks like, but loves to cook and meet new people, then a hostel will make a great choice.
Prices per night vary, but a bed or room in an affordable hostel will be cheaper than a room in a hotel. If you're travelling alone, then the downsides might outweigh the upsides, as you'll be sleeping in a room with strangers.
But if you're travelling with friends, you can book a whole room, with everyone paying for their own bed. The terms of accommodation will be exactly the same as in a hotel, but at a fraction of the cost. Along with communal bedrooms, hostels frequently have shared toilets and showers. But some rooms do have their own bathroom.