PoweraddDirect via Amazon offers its Poweradd 50-watt 6-Port Desktop USB for $25.99. Coupon code "9EA35GZN" cuts the price to $21.99. Plus, Prime members bag free shipping. (Non-members can get free shipping with orders of $35 or more; otherwise, shipping adds $5.61.) That's the lowest total price we could find by $4. It's compatible with most USB-charged devices.