Trumbull County, which encompasses Youngstown, Ohio, Warren, Ohio and Boardman, Pa., should benefit from one of the lowest unemployment rates on our list, at 4.90 percent, and the lowest median home price, at $66,950. From 2014 to 2015, rental rates in the area have gone up 3.10 percent. RealtyTract anticipates annual gross yields of 15.52 percent for thie County.