This article should help:
https://community.purpleair.com/t/view-local-sensor-output-over-wifi/5513
Try just: http://your_IP_address/
Finding your sensor IP address is a little tricky. One way is to connect to your wireless router settings page and look for something like “connected devices” or “clients” which should show the wireless device Names, MAC addresses and IP addresses. The sensor name should be something like PurpleAir-xxxx where xxxx is the last 4 digits of the sensor MAC address.
However, I don’t know if it counts against API points. I don’t think so because all the traffic stays on your LAN and does not go over the internet. However, this will need to be verified by someone who knows more about how points work.