If you have a .edu email, you can get GitHub Copilot Pro for free through GitHub Education. Here's the sign-up guide.
Copilot Pro gets you access to models from OpenAI, Claude, Gemini, Grok and more. The VS Code integration is nice but what's really useful is that you can expose all of this as a local OpenAI-compatible API endpoint, meaning any tool or script that speaks the OpenAI API just works with it, for free.
The trick is LiteLLM, which acts as a proxy between your code and whatever model backend you want. All you need is one config file.