ESP8266 is a super cheap wifi module with Tensilica L106 CPU built in. It supports wifi 2.4ghz bgn. You can get an ESP8266 board plus shipping from China for about 3 bucks. The board I’m using is ESP12E ModeMCU DevKit and it costs ￥17(about 2.5 bucks) on taobao.com.
You can find the tutorial for how to use wifi deauther on Github. The only thing you need to pay attention to is the flash settings for the type of board you have. I recommend you to use the original flashing tool provided by the chip maker. You can download it from here.
This is the flash settings for my dev board.
Here is what the ssid attack looks like.