Staples offers the 3M SandBlaster Sanding Sponge
, model no. 20908-100, for $2.49
. 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 $4. This 100-grit sponge measures 3.75" x 2.5" x 1".