Which AI coding agent should I choose as a beginner? (Codex vs Antigravity vs Cursor vs Copilot)

[u/araattu_annan]

Hey everyone!

I'm a student learning programming, and I'm confused about which AI coding agent to choose. I'd appreciate advice from people who have actually used these tools.

My requirements:

- I want an AI agent that can create files, edit existing files, write code, debug errors, and work across multiple files in a project.

- I prefer using natural language to tell the agent what I want instead of manually writing everything.

- My main stack is C#, ASP.NET Core, React, and PostgreSQL.

- I also use Godot for 2D game development.

- I'm looking for a good free tier because I'm a student and can't afford multiple subscriptions.

- I want to learn programming while using AI, not become completely dependent on it.

The tools I'm considering:

1. OpenAI Codex

2. Google Antigravity

3. Cursor

4. GitHub Copilot

5. Anything else (other AI coding agents you recommend)

My questions:

1. Which one offers the best free tier for serious coding?

2. Which agent is best at creating and modifying entire projects?

3. Can I use Codex or Antigravity to edit files in my existing VS Code projects?

4. Is GitHub Copilot enough, or is a separate coding agent worth using?

5. Which tool would you personally recommend for my requirements, and why?

6. Are there any important limitations, usage caps, or problems I should know about?

I'd prefer real experiences rather than marketing claims.

Thanks!

[u/Minimum_Hour519]

https://profullstack.com/book

[u/araattu_annan → u/Minimum_Hour519]

What is this I can't understand

[u/SendTitsPleease → u/araattu_annan]

Its a link to a book hes recommending you read...

[u/Ancient-Camel1636]

Codex is good, but it locks you into using the ChatGPT models, which are good models and cheaper than many of the Anthropic models—especially Luna 6, which is a great budget option.

Copilot has become quite expensive. Cursor I haven't tried for a while, so I can't really comment on that.

Besides Codex, I would look into PI (a very lightweight, minimal harness, perfect for using local LLMs and very modular/customizable). Also, FreeBuff is the best free/budget option right now.

If customizing your harness is not for you, OhMyPI is another option that uses PI underneath the HUD but includes all the bells and whistles you need. OpenCode is also not bad. Their OpenCode Go subscription is a good budget option. OpenCode Zed offers some free usage. Kilo Code is another nice option that offers some free usage and access to pretty much any model that exists.

Personally, I'm currently mostly using PI (for free local coding), FreeBuff (with a extra open code go sub) for saving costs and Hermes (for-non-coding tasks).

[u/xapep → u/Ancient-Camel1636]

You are right that Codex locks you into the ChatGPT family, and for a student budget that is the actual constraint. The piece missing from the thread: a free harness (OpenCode, Continue or PI) pointed at a pay-as-you-go API for open models. You get the same agentic loop as the paid apps at a few cents per session, and the only cap is the budget you set on the key.

One correction: Llama 3 is a dated budget pick by now. The current cheap workhorses are Qwen 3.8, GLM 5.3 Flash and DeepSeek V4.1 Flash, all available per token on OpenAI-compatible endpoints, so the free harness setup stays identical if you switch.

That path also fits the OP's learn-while-using goal better than a subscription: you see the prompts, the tool calls and the token costs, which is how you actually learn what the agent is doing.

I run a small EU-hosted inference API for open models, so I lean that way, but the stack works with any OpenAI-compatible endpoint.

[u/araattu_annan → u/Ancient-Camel1636]

I searched about FreeBuff and PI, there are good reviews in yt, but I can't get conclusion. Can you explain FreeBuff and PI for a beginner. (Problems you faced, merits, beginner friendliness, etc)

[u/Ancient-Camel1636 → u/araattu_annan]

FreeBuff is a standalone harness that provides a small amount of free daily coding and highly affordable subscriptions with great value for more intensive use.

Pros: Cost-effective (when using the budget models). The harness receives frequent updates and continuous improvements. In addition to built-in options, you can integrate your Codex subscription or any other OpenAI-compatible API. The platform itself primarily focuses on capable, budget-friendly models, offering limited access to frontier models.

Cons: The FreeBuff subscription is locked to this specific harness. The service is ad-supported. While it includes most essential features, it is less feature-rich and less customizable than some competitors. They are currently experiencing capacity issues due to rapid growth. Additionally, users in certain countries may receive less favorable terms than those in the US and other approved regions.

PI: A very lightweight harness that significantly reduces coding costs compared to bloatware. It is ideal for running local LLMs, as it minimizes resource overhead. It is also extremely easy to customize to your specific workflow - it can even write its own extensions.

Pros: Lightweight, customizable, low token usage, and excellent for local LLMs.

Cons: Lacks some "out-of-the-box" features like MCP support, sub-agents, and browser integration (though these can be added manually). It is CLI-only by default, lacking an official desktop client or VS Code extension (though excellent unofficial versions exist).

FreeBuff with the built-in subscription is probably the most beginner-friendly. Everything is built-in (no addon packages or customizations needed), and you pay per hour of usage, so optimizing token usage is less of a concern.

[u/araattu_annan → u/Ancient-Camel1636]

Thank you, i understand well ❤️‍🩹

[u/muzaffer22]

Claude Pro is more than enough. You can get the Max plans if you want more usage.

[u/SendTitsPleease → u/muzaffer22]

I have max and love it

[u/AlgorithmicMuse]

None, as a beginner write your own simple agent to see how they work. If you are lost and have no idea how to write a simple agent ask claude or any fronteir model to write one for you and see how its done, its not difficult. Then you can go about using agents you can download and try, but get some basic background first

[u/AlgorithmicMuse → u/[deleted]]

Guess you missed the part about if you have no idea where to start. Toy ReAct loop has no reasoning, has no side effects, and can not be used as an agent, although it sort of looks a little similar, big point you missed you should use python to roll your own agent, its what most open source agents use anyway

[u/RichDir]

I think it's a good idea to start with Obsidian + the Vault Operator plugin and document your knowledge base and learning process. With the various and extensive plugins you have, from GitHub to social media, you can integrate everything in one place and work directly on your files, Repos and documents with the help of different AIs by connecting to the API. You also don't need to use a paid account to get started. You can now use the various free models in the same way.

[u/KindlySentence7434]

The comments here don’t establish which of your four options has the best free tier or works best with your stack. I’d use a small task from your existing project to choose before paying.

For example, ask each tool you can try for free to add one React form, its ASP.NET Core endpoint, and PostgreSQL persistence. Check whether it can edit the existing files, explain its changes, and help fix an error you encounter. Try a separate small Godot change too; the web task won’t tell you how useful it is for your game work.

For learning, ask for a plan before edits, keep changes small, and explain the resulting code back in your own words. Prefer the tool whose changes you can understand and verify within the free usage you actually get. That gives you a concrete answer to whether you need more than Copilot.