Staples offers the Pentel Hi-Polymer Large Block Eraser 3-Pack in White, model no. ZEH10BP3-K6, for $2. Plus, Staples Rewards members bag free shipping. (Not a member? It's free to sign up.) That's the lowest total price we could find by $5, outside of the price below. These erasers are non-abrasive. Deal ends September 19.
Note that Amazon offers it to Prime members for $2.28 with free shipping.