It's not uncommon for B&Bs to have a two-night minimum, especially in popular weekend-getaway spots. Although more B&Bs now take credit cards, they may add a service fee to your bill. Others are still cash only.
Depending on what country you're traveling in, bed-and-breakfasts go by different names (and may not include breakfast at all). In Germany, Switzerland, and Austria, B&Bs are known as Zimmer Frei or Privatzimmer. These are common in tourist areas, such as Austria's Salzkammergut Lake District, Germany’s Rhine region, and southern Bavaria.
In rural Spain, look for a cama or casa particular. In Croatia and Slovenia — where mass tourism and overpriced resort hotels reign — private rooms called sobe are often the best deal going. France's chambres d'hôte, mainly in the countryside and in small towns, are usually listed only through tourist information offices. While your hosts likely won't speak English, they will almost always be happy to share their home.
I especially enjoy staying at farmhouse B&Bs, such as those in Britain or in Italy (where they're called agriturismi). Like in the US, many family farms are struggling to survive. By renting rooms to travelers, farmers can remain on their land and continue to produce food. Not only do farmhouse B&Bs provide a quiet, restful place to call home, but they can also give you a peek at some fun traditions, such as a hot-water bottle for the bed to warm it up at night.
B&Bs are the next best thing to staying with a family. Even if hotels weren't more expensive, this budget alternative can be your best bet for a wonderful, culturally intimate experience.
Rick Steves (www.ricksteves.com) writes European travel guidebooks and hosts travel shows on public television and public radio. Email him at email@example.com and follow his blog on Facebook.