I need to find a free/good agentic AI (maybe open source)

I need an "agentic" AI, or in other words, an AI that can access my PC and its files and folders for the upcoming university year.

For 2 years i used GitHub Copilot and applied for a student plan which is free. That plan used to help me get so much work and projects done at very short notice. It was limited to a monthly usage quota but it was enough. How I used it? Since it didn't have an app that can interact with my files and system, I use it inside of VS Code and give it access to a certain folder. I use Linux as OS and sometimes things break, so I tend to fix them with the AI agent by giving it access to the whole PC so it can do the troubleshooting for me.

For my bad luck they made a lot of changes and updates to it, and now the monthly quota runs out in the matter of an hour or two.

And since I am a student with no job, I can't afford paying for one, any open source solutions that you guys tried and achieved?

OS: Ubuntu.

Even if I gave up on looking, and wanted to pay a subscription for let's say Claude or ClaudeCode I can't pay for it using a regular card.