Amazon offers TP-Link AC750 Dual-Band Wi-Fi Range Extender for  with free shipping with Prime.

Product Description:

Dead spots = huge bummer. Ditch the dead zones and enjoy better whole-house coverage with this small but mighty gadget.
It just pops into any existing outlet, unlocking better Wi-Fi coverage, whether you're a sports fan, movie buff, or gaming guru.
Connect up to 20 devices over Wi-Fi. This range extender also has a fast Ethernet port so you can enjoy wired speed and reliability for your favorite device.
Dual-band Wi-Fi enables 2.4 Ghz and 5 Ghz bands for connectivity.