Many countries have YHAs, which have reciprocal agreements with one another. However, if your country does not have it, you may join at your country of destination. Membership is relatively inexpensive, but will vary depending on the country. An individual membership also pays for the individual’s children, but there is also a joint/family membership for a 2-partner family. For those between 16 and 25, there is a discount rate. There are also discounts for various groups.
The different hostels we stayed at varied in the number and type of accommodation. Some only have dormitory-style rooms, where you shared with several others. Some have private rooms for families or other groups travelling together. Some have separate male/female rooms, whereas others have co-ed rooms. Some are in old mansions or castles, while others are in cabins or old hotels.
During our trip, we were sometimes roomed together and other times, roomed with others. It was interesting to make new friends who came from so many different areas of the world. Not only that, you had to share the kitchen, where you prepared your own food. If you wanted to, you could have shared your meal with other groups. Be prepared also to share bathrooms.
You can reserve rooms at the hostels in advance. Or, if you find yourself in a city without prior arrangement, you may be able to find room at the local hostel. The different hostels are individually run, so some may make room for you, even if they are completely booked.
Although hostels will welcome non-members, members receive discounts on their stay. Those who are non-members may take a temporary membership, which gives them a discount, but not as deep as for members. Membership has other benefits, such as discounts on travel, shopping, and tourist attractions. They even have their own discount calling card.
For those who are adventurous and do not care for all the luxuries of a hotel, youth hostelling provides an inexpensive alternative to accommodations.