I'm building a piece of open source code that I want to use the AGPLv3 license, but at the same time, if a company pays a fee, I want to allow them to access the software using a much more permissive license such as the MIT license or the Apache license.
I'm a bit unsure about a couple of things, though. Is this even allowed? Also, how does once apply this to your codebase? The standard practice is to have a LICENSE.txt file in the root of your project which (in my case) contains the AGPLv3 license text. It is also common practice to include a shorter version of the license text at the top of every source code file to emphasise which license applies to which files.
If I wanted to do this should I include two LICENSE.txt files in the root of my project and two shortened license headers at the top of each file and then in the readme state that the MIT license is only applicable if you pay a licensing fee?
I have no idea how an open-source project handles this particular problem. Any help is appreciated.