For many veterans, the prospect of free money from the government just seems too good to be true. Around 145,000 troops who were kept on duty beyond their original discharge date due to the Sept. 11, 2001 attacks are eligible for cash bonuses totaling $324 million, but no one seems to want to collect them. Under a measure passed last October, military personnel who were forced to remain on duty because of the “stop-loss” policy, are eligible for $500 in back pay for each month of involuntary service — the average sum owed is between $3,500 and $3,800. Thousands of veterans, however, have ignored the letters reminding them to file the paperwork to collect their checks. "It is unusual, and because it's unusual maybe that's why some people are questioning whether this is legitimate," said the Pentagon official in charge of enlisted personnel management. "We knew it was going to be a challenge," he added. "As a military culture, we generally don't pay people for services rendered; we pay them when they serve."