The cross-over point is about 15 times annual rent, [trulia] believes. In other words, as a rough rule of thumb, homes are probably fairly valued in a city when they cost about 15 times a year’s rent. So, for example, if you’re paying $10,000 a year to rent a place, think twice about buying a home that costs more than $150,000. Dean Baker, economist at the Washington, D.C. think-tank The Center for Economic and Policy Research, came to a similar conclusion in research on the subject in recent years. Fifteen times is the historic average, he said. Brett Arends at the Wall Street Journal