The printer routinely sells for as little as 30, that is where I got the number from.
Regardless of the cost, it is still at the base end of the feature spectrum.
While the printer does have a wireless capability, meaning it can be connected to your home wifi network, that will give you only wireless printing/scanning from computers and some android devices (via google cloud print). This model still lacks a specific "airprint" protocol however.
It seems you are asking a different question than you had posed initially.
There is no need to disprogram the brother, simply turn it off or disconnect it from your network (unplug).
You can then install the canon on your computer(s). Again though because it is a very simple model, and lacks a touch screen, you have to connect it to your network manually, by plugging the printer into your computer with a usb cable then using the canon software to "teach" it how to access your network.
At that point the usb can be unplugged for wireless use (but still not by airprint, which is outside the capabilities of this model, the best you can get is the app I mentioned).