They are still quite common in the UK, but they are mainly seasonal in coastal holiday areas. My late mothers parents ran a guest house and during the summer peak, she and her brothers slept in a tent in the garden so that her bedroom could be rented to guests. She was born in 1903, but I still hear similar cases today,
You mean like paying rent? Check out WWOOFing arrangements. You can volunteer on a farm in exchange for free room and board.
I searched Craigslist in response to the thread title. It looks like the whole Room & Board idea is a thing of the past. That, or they just aren't on Craigslist. Maybe there's a site for Hostels? Yep.. Good old google turned up this site. Hostels.com - Great deals on hostels anywhere! I would check there if I were looking for anything like that. My understand of hostels is that they do some of that, but not all. You might find that they offer a sack lunch and that's it, or it may be exactly what you need. But I'd bet you have to call around a little bit to find out. Are you planning on traveling?