A socialist internet (referring to a mode of socialism that is not corrupt) is not an internet where the rich pay a tax to give internet services to all, but rather an internet where no payment is required for most services, excluding some payed parts that contain features purely for convenience (such as removing ads). It is important that these features be only for convenience and not limiting any actual functionality of the program, as that would not be true socialism. In this method, people with more budget who use the service help support it voluntarily for those who have less.
This method would allow anyone to create their own socialist internet program, and actually get money from it, while it still remains free to anyone who can't or doesn't want to pay. Additionally, programs will get money proportionate to their users, and still with no requirement for taxing internet usage. Finally, fees should be payed one-time rather than on a subscription to increase monetary stability and happiness within the system.
A socialist internet can come true without the need of any government or ruling body. It can come true by the will of the people, the will of the creators of websites and programs. People will always move to the better alternative if informed enough. Those creators are you, reader. Make a difference.