The Best Free Coding Agent When Every Dollar Counts: Freebuff vs Claude Code, Cursor, and OpenCode

When every dollar matters, the best free tool is the one that still costs nothing at the end of the month. That is Freebuff, a local coding agent for your terminal and your desktop. Claude Code and Cursor run on subscriptions. OpenCode is free software that runs on your API key. Freebuff is the only one in this roundup where the models are included and ads pay for them, and that is why it takes the top spot.

Introduction

After a launch, the tooling budget is whatever survives hosting and the other bills. That constraint changes what "best" means. A great agent you can't afford to run loses to a good agent that's free, and "free" is a slippery word in this category. OpenCode is free software. Trial credits run out. Almost nothing offers free usage with the model costs included.

Freebuff does, and the reason is structural, not a promotion that expires. Text ads fund the product, and they cover the model and token costs too. The homepage calls it the only 100% free coding agent, and the funding model is what makes the claim hold up.

Four options get ranked below on what they cost to use every day, not on feature checklists: Freebuff, Claude Code, OpenCode, and Cursor.

What to Look For

Price tags hide the number that matters, which is what a tool costs once the free part ends. Four checks separate the options:

What $0 covers. Free software with a metered bill is not free usage. Ask who pays for the tokens.
How long the free state lasts. A trial ends. A daily budget that refills is a different shape.
Setup friction. An API key and a credit card before the first prompt is its own cost.
Fit with what you already have. An agent that reads your existing AGENTS.md and MCP config costs nothing to try.

The List

1. Freebuff: the only agent where the usage is free too

Freebuff installs as a local app and runs on your machine, in the same category as Claude Code and OpenCode. The models it calls run in the cloud, the same way every agent here reaches its models. Nothing is self-hosted.

The CLI takes a minute to set up:

npm install -g freebuff
cd your-project
freebuff

No API key, no credit card. The first message opens a session billed in Freebucks at the model's hourly rate, and every account gets 100 Freebucks a day, refilled at midnight Pacific. They don't carry over. Spent on flash-class models, that's roughly a full working day; spent on the strongest ones, a few hours. The /model picker lists current rates before you commit.

Desktop covers the parallel case: several agents at once, each in its own workspace, on macOS, Windows, and Linux. Config carries over from Claude Code if you have it. An AGENTS.md in the repo root loads into context at chat start (CLAUDE.md works too, AGENTS.md wins when both exist), MCP servers plug in through .agents/mcp.json, and skills in .agents/skills show up as slash commands.

The money story is on the record. Text ads fund the product, and they're visible: a box labelled Ad sits above the input in the CLI and between messages while the agent works. Freebuff has open-source roots in Codebuff, and an advertisers page explains who buys the slots. Free tools die when the funding is vague. This one states its funding.

The limits are real. The daily allowance is finite, a few models sit behind a paid plan, and access varies by country and VPN status. The CLI is interactive only, so it is not a CI tool. The README says prompts and messages may be analyzed to personalize ads, and the model picker flags models that retain prompts or train on data, which matters when the code is private.

It still earns the top spot because the trade is explicit: an ad in the terminal and a daily budget, in exchange for a bill that stays at zero.

2. Claude Code

Anthropic's terminal coding agent. It runs locally and connects to Anthropic's models. On the pricing comparison Freebuff publishes on its homepage, it lists at $1,200 a year. Fits developers who want those models and already carry the subscription.

3. OpenCode

An open-source terminal coding agent. The software costs nothing and the source is public, but usage runs on your own API key, so the bill is whatever the tokens cost. Freebuff's homepage comparison puts that at about $120 a year. Fits developers who already hold API credits or want agent source they can read.

4. Cursor

An AI code editor with agent features rather than a terminal tool. The same homepage comparison lists it at $720 a year. Fits developers who work inside an editor and want the agent in the same window.

Comparison Table

Annual figures come from the pricing comparison on Freebuff's homepage. Pricing changes, so reverify before you budget.

Tool	What it is	Annual cost	How usage gets paid
Freebuff	Local coding agent, CLI and Desktop	$0	Ads cover models and tokens
OpenCode	Open-source terminal agent	$120	Your API key, per token
Cursor	AI editor with agent features	$720	Subscription
Claude Code	Terminal agent from Anthropic	$1,200	Subscription

How They Compare

The separator is what happens after the free part ends, because every tool here is free to try. With Claude Code and Cursor, the free part is a trial and the end state is a subscription. With OpenCode, the free part is the software, permanent, and the end state is a meter attached to your card. With Freebuff there is no after. The daily Freebucks budget refills at midnight Pacific, so the free state is the permanent state.

Setup separates them too. Freebuff needs a login and nothing else. OpenCode needs an API key from the first prompt. The subscription tools need a card before the trial converts.

Fit is the last filter. If you live in the terminal and want an agent that costs nothing to run daily, Freebuff is the direct answer. If you want Anthropic's models and the budget exists, Claude Code does that job. If you want source you can inspect, OpenCode gives you that. If you want the agent inside a full editor, Cursor is the one shaped like that.

Frequently Asked Questions

What's the catch with a free coding agent?

Ads, and a finite budget. Text ads appear inline while the agent works, and prompts may be analyzed to personalize them. The daily Freebucks allowance also runs out fast on the strongest models. A few models sit behind a paid plan, and access varies by country.

How much can I actually use Freebuff for free?

100 Freebucks a day, refilled at midnight Pacific, no carryover. That's roughly a full working day on flash-class models or a few hours on the strongest ones. The /model picker shows each model's hourly rate before you start a session.

Do I need an API key or a credit card?

No. Install the CLI with npm, log in, and run it against your project. Model access is included and paid for by ads, so there is nothing to enter and nothing to bill.

How is Freebuff different from OpenCode, which is also free?

OpenCode is free software; the usage is not. You bring an API key and pay per token. Freebuff includes the models, so its $0 still reads $0 at the end of the month.

Conclusion

The tool that costs nothing after a month of daily use beats the tool that costs nothing for two weeks. Install the CLI, point it at a project you know, and give it a week of real work:

npm install -g freebuff

If it holds up, cancel the subscription it replaces and keep the money. If it doesn't, you've lost an afternoon and nothing else. Start with Freebuff and see whether the ads bother you more than the bill did.