Cheap basic lodging: hostels
One of the cheapest accommodation types is the (youth) hostel. Swiss hostels in general are of good quality, but rooms are basic. Staying in a dormitory (e.g. 6 or 12 beds per room) is the cheapest way to spend the night. Second best from a price point of view are private rooms with shared bathrooms in the corridor. Most hostels also offer rooms with a private bathroom.
Other budget hotels
Youth hostels are not the only option. There are affordable basic hotels as well, even on top locations. The best ones can be found here.
Book a hostel
You'll find a lot of Swiss hostels here: