Philadelphia plans to launch One Philly Mortgage, the nation's first city-backed mortgage program, aiming to ease home buying. It offers 30-year fixed loans with interest rates 1% below market, no private mortgage insurance, and down payments capped at 3%. The program supports buyers with credit scores as low as 620 by using a city-backed loan loss reserve, potentially saving a $200,000 homebuyer about $3,400 annually.