For anyone who has interest, TP-Link has various kinds of mesh wifi system on sale:
1. TP-Link Deco Mesh WiFi System (Deco S4) – Up to 5,500 Sq.ft. Coverage, Seamless Roaming, Parental Controls, Works with Alexa, 3-pack —$134.99 (Lowest Price Ever)
2. TP-Link Deco Mesh WiFi System(Deco M3) – Up to 4,500 sq.ft Whole Home Coverage, Seamless Roaming, Parental Controls, Plug-in Design, Works with Alexa, 3-Pack –$98.99
3. TP-Link Deco Mesh WiFi System(Deco M5) –Up to 5,500 sq. ft. Whole Home Coverage and 100+ Devices, Parental Controls/Anitivirus, Seamless Roaming, 3-pack —$149.99