This is an amusement token. To avoid the appearance of gambling, winners were issued these "good for" tokens instead of cash. Over time proprietors began to exchange cash for these winning tokens instead of merchandise. As a result, there was a government crackdown, resulting in the many variations of "No cash value -- For amusement only" designs. My understanding is that the number corresponds to a particular establishment and/or machine. Are there any refinements to this understanding?