Sabrent via eBay offers the Sabrent 50-watt 5-Port Desktop USB Charger in White, model no. AX-U5PW, for $9.99 with free shipping. That's $4 under our May mention and the lowest total price we've seen. (It's the best deal now by $7.) It features up to 2.4 amps per port (10 amps max) and is compatible with most USB-charged devices.
Also available is the Sabrent 40-watt 4-Port Wall Charger in Black, model no. AX-U4PB, or White, model no. AX-U4PW, for $8.99 with free shipping. That's the lowest total price we could find by $5. This charger delivers 8 amps between four ports or up to 2.4 amps per port.