I am not sure there is a totally free and open source copilot alternative if that's what you are looking for.

As a student you shouldn't worry much about it. Your employer would most likely provide you copilot or a similar product.

I used to use Tabnine before GitHub copilot was a thing. Copilot is well worth the money if you can afford it and in its own league but Tabnine is better than nothing and can run on your machine.

I’m expecting more Open-source alternatives soon thanks to llama.cpp and similar.

I have used Tabnine before, is it not free too?

You can try Codeium.