My local co-op had them as impulse items at the checkstand. I seem to remember them costing as much as a candy bar, and my parents giving in and getting me a f

My local co-op had them as impulse items at the checkstand. I seem to remember them costing as much as a candy bar, and my parents giving in and getting me a few. IIRC, they were slightly stronger than ceramic magnets, and much less brittle.