Amazon offers Prime members the Pentel Hi-Polymer Large Block Eraser 3-Pack in White, model no. ZEH10BP2F, for $1.46 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, shipping costs $6.14.) That's pennies under our August mention and the lowest total price we could find by $2. These erasers are non-abrasive.
Note that this item will ship in two to five weeks.