Seventh Continent via Amazon offers Prime members the NRGized USB 3.0 4-Port Portable Hub
(pictured), model no. M-325, for $9.99
with free shipping
. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping adds $6.94.) That's $30 off and the lowest total price we could find. It features over-current, over-heating, over-voltage, and short-circuit protection.
Also available is the NRGized USB 3.0 4-Port Aluminum Portable Hub
with the same shipping options as above. That's $30 off and another price low.