 Brought to you by the U.S. Department of Health and Human Services and the Ad Council. Thanks for spending time with us. Would you let a stranger vacation in your home if you got free lodging in return? A free stay in someone else's home along a budget-friendly way to travel has become more appealing as costs rise and travelers seek out local vibes. Here's Allison Pauley at the Wall Street Journal. Allison, explain the trend.