"The "Thin Dime" play coin was part of a "Mint-O-Money" package of play coins and paper notes, which originally sold for 29¢ in the 1940's or 50's. These, along with a variety of other play money, were made by Tracies Industries of Holyoke, MA. Later, as Tracies increased the price to 89¢ and added other items to the package, Kresge's (now K-mart) began selling Japanese-made imitations of the coins, and those in turn were followed by copies made in Hong Kong and Taiwan. Yours appears to be one of the originals, however."
Source: Treasurenet posting by PBK (perhaps the best researcher who ever was on T-net) on 12/11/07, post #9 here: .
http://www.treasurenet.com/forums/what/66405-thin-dime.html
Don.....