ChatGPT Launches Sol and Luna — Prices Cut in Half, Latest AI Now Open to Free Users
OpenAI released GPT-6 Sol and GPT-6 Luna on September 22, 2026. API prices are slashed 50% compared to GPT-5.6, and Luna is now available to free users via the desktop app. Both models improve factual accuracy and coding error rates — a dual-model lineup built for cost-conscious use.
On September 22, 2026, OpenAI released two new AI models: GPT-6 Sol and GPT-6 Luna. Prices have been cut to less than half of what they were before, performance has improved — and Luna is now available to free users too.
What Is It?
GPT-6 Sol and GPT-6 Luna are smaller, more efficient models built using the same training methods as GPT-6 Astra — OpenAI's flagship model released earlier this year.
They're designed for users and businesses who want solid performance without the premium price tag. By making the models more compact, OpenAI reduced the cost of running them (inference cost) and passed the savings on to users.
What Has Changed? (Sol vs. Luna Explained)
With GPT-5.6, API pricing was $4 for input and $20 for output (per 1 million tokens — a unit similar to character count). Free users were limited to lower-capability models, and accessing the latest models required a paid plan.
Sol's API pricing drops to $2 input / $10 output — a 50% reduction versus GPT-5.6. Luna goes even further at $0.10 input / $0.50 output. And Luna is now accessible to free users via the desktop app.
Here's a quick comparison of the two models:
| Feature | Sol | Luna |
|---|---|---|
| Positioning | High accuracy, professional use | Lightweight, cost-focused |
| API Input Price | $2 / 1M tokens | $0.10 / 1M tokens |
| API Output Price | $10 / 1M tokens | $0.50 / 1M tokens |
| Free Users | Not available | Available via desktop app |
| Best For | Coding, precise business tasks | Everyday questions, light tasks |
Both models also show improvements in factual accuracy and coding error rates. In other words, they're not just cheaper — they're more reliable too.
How Can They Actually Be Used?
Sol and Luna are currently available in two places: ChatGPT Work and Codex (OpenAI's coding tool).
Using Luna (for free users) Install the ChatGPT desktop app (the PC application) and you can access Luna right away. Note that it's not available in the browser version. Luna is well-suited for everyday queries, summarizing text, and light research tasks.
Using Sol (for paid plan users) Sol is included in the ChatGPT Work plan. It's the right choice for tasks that demand accuracy — business documentation, coding projects, or anything where mistakes are costly.
The biggest headline here is that Luna is now open to free users. Until now, free-tier models came with significant capability limits. With Luna, anyone can experience a GPT-6 generation model without spending a cent.
Here's a simple rule of thumb: use Luna for everyday things like quick questions, casual conversation, or drafting a short email. Switch to Sol when accuracy matters — important documents, coding, business writing, or translation where getting it right is critical.
Luna is only available through the desktop app — not the browser version of ChatGPT. Free plan users of Luna also have a daily usage limit. If you hit that limit, access will be paused for the rest of the day, so plan accordingly.
What Does It Cost?
- ✓Available via desktop app
- ✓Best for light tasks
- ✓Daily usage limit applies
- ✓Higher accuracy
- ✓Ideal for coding
- ✓API at $2 input / 1M tokens
API refers to the technical connection point used to integrate AI into your own apps or systems. For everyday users who aren't developers, you don't need to worry about API pricing — you'll access Sol and Luna through ChatGPT's apps and services directly.
Summary
With the arrival of GPT-6 Sol and Luna, OpenAI's AI has become more accessible than ever. Prices drop by up to 50%, and free users can now try a GPT-6 generation model for the first time.
If you're new to AI, the easiest first step is to install the ChatGPT desktop app and try Luna — no cost, no commitment, just the latest generation AI at your fingertips. If you're thinking about using AI seriously for work, the ChatGPT Work plan with Sol access is worth a look.
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