It is remarkable that the Japanese erasers retail for $1. The quality and design is only of the caliber that we expect from Japanese manufacturers. There is very little in the world of collectibles that sells for so little money.
The importer for Iwako and Dream/Zensinsyoji, BC USA, makes only a penny or two per eraser they sell, especially with the current exchange rate between the dollar and the yen. The dollar buys fewer yen than it used to, thus it is more expensive to buy Japanese erasers. Yet BC has held the price on the wholesale cost of Japanese erasers.
The price increase for the new Japanese toy erasers will apply for only a few of the styles. For now, I suspect most of the retailers of Iwako and Dream/Zensinsyoji erasers will stay at $1, but sometime next year the prices at retail for the Japanese erasers will rise.