BOSTON ( TheStreet) -- Buying a home seemed too risky to many Americans during the housing bust, but here's a look at five U.S. markets where prices have fallen so low you'd be crazy to rent. "These are places where prices have in some cases fallen more than 50%," says Svenja Gudell, senior economist at market tracker Zillow.com ( Z). "They're forecast in many cases to rise really, really strongly because there's no place to go but up." Zillow analyzed hundreds of housing markets recently to see how long buyers in each locale would need to "break even" -- pay the same in mortgage payments and other expenses (minus any capital gains) that they'd spend on rent. Gudell says renting makes more sense than buying if you don't stay in a home long enough to reach the break-even point, but buying becomes the better deal thereafter. Zillow found that break-even points range from one year in Memphis, Tenn.'s Shelby Forest-Frayser neighborhood to 20.3 years in Virginia Beach's upscale Sandbridge area. The average U.S. community has a 3.1-year break-even period. Here's a look at places offering the shortest break-even points among America's 30 largest cities. Zillow calculated break-evens by estimating each community's median home price, median rent, typical property taxes, expected future price appreciation and other factors. All figures are as of March 31 and refer to Zillow's estimates of prices and rents for all houses, condos and co-ops (including those not on the market) in each metro area.