Airbnb has quickly become one of the premier rental sites, with over 600,000 listed properties world wide, including more than 600 castles.
Choose a location, set your dates and number of guests, and then pour though your options.
Use the filters to narrow them down.
People like Airbnb for their easy to use site, the $1 million insurance policy for hosts and, of course, the originality of listings.
The Home Away Family and Vacation Rentals both are at 950,000 rental properties worldwide.
Its websites, like vrbo or vacation rentals by owner and vacationrentals.com, are also easy to navigate and let you fine tune your search results with filters for amenity and price.
If you really want to save money on your next vacation, consider swapping your house with travelers from another city or country.
HomeExchange.com is a great place to start.
Browse properties in your desired city of travel or choose a destination based on who wants to stay in your city.
In San Francisco, I'm Kara Tsuboi, CNET.com for CBS News.