The first 802.11ax routers were unveiled a Computex 2018, before the WiFi Alliance decided to use a new consumer-friendly naming scheme and rename 802.11n to WiFi 4, 802.11ac to WiFi 5, and 802.11ax to WiFi 6, and then WiFi 6 routers launched later that year from companies such as ASUS and TP-Link with price starting at $350.
Prices have now come down with for example TP-Link WiFi 6 AX3000 smart WiFi router going for $142.99 plus shipping on Amazon, and Xiaomi has now launched their own WiFi 6 router with Xiaomi AIoT Router AX3600 offered for $135