Hostels often offer private ensuites for a fraction of the cost, especially in off season, that one could find at a budget hotel. Staying in dorm-style rooms is inexpensive, at the cost of your privacy. You will make friends.
Hostel proprietors often provide: trip itineraries, night-life recommendations, walking tours, pub crawls, and bike hiring, to name just a few possibilities. This is an excellent opportunity to leave your comfort zone, in a friendly atmosphere.
Surfing and B&B
CouchSurfing, and AirBnb offer a inexpensive, or free in the case of Couchsurfing, opportunity to meet and hang out with the locals. Gaining this sort of perspective on a new city is worth more than money can buy. Additionally, while some scoff at the idea of couch surfing, I have to report that a couch in a private home can be a welcome respite from the otherwise terribly low hotel standards of some countries.
Perhaps we’d like to rough it even further, to the edges of civilized comfort. Why not explore Camping ? One of my favorite European adventures revolved around camping out at night, providing an unforgettable, mostly positive, experience. More on this trip in later features.
If you MUST have a hotel room, there are tons of sites devoted to finding them.
Booking being just one.