TITLE: OpenAI Halves the Cost of GPT-6 Sol and Luna for Businesses DATE: 2026-09-27 COMPANY: OpenAI TOPIC: Model Releases SUMMARY: OpenAI released GPT-6 Sol and Luna on 23 September 2026, cutting API prices by 50 per cent compared to the previous GPT-5.6 generation. GPT-6 Sol, the mid-tier model in the GPT-6 family, now costs $2 per million input tokens and $10 per million output tokens, while making roughly half as many factual errors as its predecessor. Both models are available to all paid ChatGPT tiers and through the OpenAI API immediately. WHAT CHANGED: OpenAI released GPT-6 Sol and Luna on 23 September 2026, filling out the GPT-6 model family below the previously launched GPT-6 Astra flagship. Both models launched with permanent API price reductions of at least 50 per cent compared to their GPT-5.6 predecessors. OpenAI attributed the cuts to structural improvements in caching and inference efficiency rather than a promotional campaign. GPT-6 Sol is positioned as the mid-tier everyday model, with a 1,050,000-token context window and support for text and image input. OpenAI says Sol makes approximately half as many factual errors as GPT-5.6 Sol, with independent testing showing maximum-effort hallucination rates dropping from 92 per cent to 60 per cent. The company describes Sol as approaching GPT-6 Astra capability on general tasks while costing significantly less to run. GPT-6 Luna occupies the lightweight, high-volume tier, priced at $0.10 per million input tokens. Luna is now accessible to ChatGPT Free and Go users through the desktop application, as well as to all paid tiers through the API. Both models are rolling out gradually to ChatGPT Work and Codex for Plus, Pro, Business, Enterprise, and Edu subscribers, with API access available immediately. OpenAI said the pricing reductions reflect efficiency gains from improved caching and inference optimisation, suggesting further reductions may follow as the company refines its infrastructure. WHY IT MATTERS: The 50 per cent price reduction on Sol moves the cost-per-task calculation for AI-assisted workflows into territory where it is cheaper than the time saved in many common business processes. GPT-6 Sol's improved accuracy, roughly half the factual error rate of its predecessor, makes it more suitable for customer-facing content, research outputs, and any task where an incorrect answer creates a problem. The tiered model structure (Astra, Sol, Luna) gives businesses a clear routing strategy: high-stakes complex tasks to Astra, everyday professional work to Sol, and high-volume lightweight tasks to Luna. OpenAI attributed the pricing change to structural efficiency gains, suggesting further reductions are possible as infrastructure matures. Luna access for Free and Go ChatGPT users expands the number of employees who can experiment with AI assistance, lowering internal adoption barriers for teams that have not yet embedded AI into daily work. The move continues a pattern across the industry where frontier AI has become substantially cheaper over 12 months, driven by competition from open-weight models and Chinese AI providers. DAVID & GOLIATH ANALYSIS: OpenAI's price cuts matter most to the businesses that were on the margin of making AI work economically. For a company that processes hundreds of documents a month, routes customer enquiries through an AI assistant, or uses AI to draft and personalise sales outreach, the cost model at $2 per million tokens for Sol is now very different from what it was at $4. For a company using Luna at $0.10, the economics of high-volume, lightweight AI tasks have crossed into near-zero marginal cost territory. The risk for lean operators is not that they pay too much. It is that they wait. The businesses that built workflows on GPT-5.6 at higher prices are already ahead. At lower prices, those same workflows become available to smaller teams with tighter margins. This is the moment to revisit any AI use case that was shelved because the numbers did not quite work, to rerun the cost calculation with the new pricing, and to move from evaluation to implementation on at least one operational workflow. The immediate recommendation is practical: if you have a ChatGPT Work or API subscription, calculate what you spent on AI calls last month and confirm your projected spend at the reduced rates. Then identify one workflow where you were limiting AI usage because of cost, and remove that constraint. RELEVANT SYSTEMS: AI Growth Engine, Employee Amplification Systems SOURCE URL: https://davidandgoliath.ai/daily-ai-briefing/openai-gpt-6-sol-luna-fifty-percent-price-cut FEED URL: https://davidandgoliath.ai/daily-ai-briefing/feed --- Published by David & Goliath | https://davidandgoliath.ai Daily AI Briefing: one AI development per day, decoded for business operators. This is a structured companion file optimised for LLM retrieval and citation.