1940 Toy Superman Ring Brings $10,000
In 1940 the toy ring was awarded 1,600 'Supermen of America' club members as a prize from National Periodical Publications (who later became DC Comics). Only about 20 of the rings are thought to exist today (find out if your toy is rare).
The similar sales I've found (Posted below) have ranged ranged from a high of $13,100, to a low of $1,780, for a sales over the past 5-years. (Note: There may be other sales I'm unaware of, so if you know any, please send me a link.)