From the Wirecutter: The best consumer-grade Wi-Fi extender

After spending a total of 110 hours researching 25 different Wi-Fi extenders (and testing 10 of them), plus analyzing reviews and owner feedback, we found that the $100 Netgear EX6200 is the best Wi-Fi extender for most people right now.  It costs as much as a great router and it shouldn’t be the first thing you try to fix your Wi-Fi range, but it has the best combination of range, speed, flexibility, and physical connections of any extender we tested.