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Buy.com has this [ChargeBlock iPhone Battery Charger for $17.99 with free budget shipping. This is the best total price we could find by $15. This compact battery charger works with all iPhones and most iPods (except the shuffle). It lets you use your phone even while it is charging, so you don't have to worry about it running out of juice before you finish your call. Sales tax is only charged in CA, MA, MD, NY, and TN.