the replacement of Arduino wifi shield

We have a lot of Arduino UNO boards that were bought many years ago . I need to buy Arduino wifi shield in order to teach students wifi projects. The Arduino website says this product was retired. Can anybody tell me what is the product that I can use to replace Arduino wifi shield? I don’t want to buy something that cannot be used. Thanks a lot!

I use the ESP8266 E-12 node MCU
One by HiLetgo at Amazon (cheaper elsewhere) < $9 USD

I just posted a use at:
Example post.

Node MCU can replace Uno as a single package, WiFi included. It is progammed with the Arduino IDE.
https://tttapa.github.io/ESP8266/Chap01%20-%20ESP8266.html