Sunvalleytek via Amazon offers the RAVPower Desktop Charging Cradle & Sync Dock for Samsung Galaxy S4 in Black (pictured), model no. RP-UC04, bundled with the RAVPower 2,800mAh Li-ion Battery for Samsung Galaxy S4, model no. RC-B600BE, for $37.58. (Add both items to your cart to see this price.) Apply coupon code "ANNZHV63" to drop the price to $23.59. With free shipping, that's $38 off and the lowest total price we could find. The dock features a USB charging dock and a separate cradle for charging your battery. The battery features over-heating, short-circuit, over-charging, and over-discharging protection.