The battery-powered Philips One Power Toothbrush by Sonicare drops from $24.99 to $14.95 with free shipping at Philips. You can find this same discount for these brushes at other stores. However, only Philips is offering free shipping, which makes this the best deal, since other stores are charging anywhere from $6 to $10 in shipping fees for these toothbrushes. A single AAA battery can keep these brushes powered for up to three months. Sales tax is charged in most states.