Freddie Mac said in a statement Thursday that the average interest rate on a 30-year fixed-rate mortgage was 6.46 percent, down from 6.49 percent last week. Borrowing costs fell sharply after topping 7 percent earlier this year, boosting home buyers' purchasing power and prompting some would-be buyers to give up the wait-and-see. The National Association of Realtors (NAR) reported Thursday that sales of pre-owned homes in the U.S. rose in July for the first time in five months. While pre-owned i...