There are many ways to save a bit of money when traveling. One that has a varied reputation is using Hostels. They are not just in Europe, you know.
When choosing a hostel, commonly called Youth Hostels, look for ones through associations, land trusts and easily found in several references. Some are listed only in one place and may not have the best reputation.
Try online resources like Hostels.com for almost instant reservations at listed hostels. Hostel World is recommended by a few people I know who use hostels in the US, but have not heard anything about the Europe hostels.
Each hostel will have a different set of rules. Many don't have sheets or blankets, so always bring your own sleeping bag, just in case. Some make you pay for water use and almost all expect you to clean up after yourself as part of the rental of the sleeping space. Some have kitchen facillities and may even provide some sort of meal, but don't depend on that.
For just a few dollars or euros, you will have a place to put yourself and your stuff for the night. That is about it.