Letting strangers sleep in your home may be the answer to low-cost travel. It’s called house swapping, which you might remember as the plot of the hit 2006 rom-com The Holiday. Here’s how it works: Two parties agree to exchange homes for a set period, at no cost to either. It’s becoming an attractive option as travel costs continue to climb. One estimate says that a family of four can save up to $2,000 a year on vacations with house swapping. If you want in, first make sure your home insurance covers temporary guests. Next, sign up for a reputable platform like HomeExchange or Intervac, which typically have annual membership costs ranging from $100 to $300. Once you've created your listing, you can browse other homes all around the world. Negotiating a great swap can take time, so make sure to get on it early and prepare to exercise some patience. Once your swap is set, enjoy your vacation and live like you're in The Holiday (though Jude Law is, sadly, not included).