GPT-6 Luna priced at $0.10/$0.50, half of GPT-5.6, as Anthropic and OpenAI spark a price war
altryne · x · 2026-09-23
Simon Willison reviews the same-day releases of Claude Opus 5.5 and GPT-6 Sol/Luna, highlighting a new price war:
- GPT-6 Luna costs $0.10/M input and $0.50/M output — half of GPT-5.6 Luna ($0.20/$1.20) and among the cheapest models OpenAI has ever shipped, behind only the far weaker GPT-4.1 Nano and GPT-5 Nano
- GPT-6 Sol lands at $2/$10, a steep cut from GPT-5.6 Sol's $4/$20; the identically priced GPT-5.6 Terra now has no reason to exist
- Claude Opus 5.5 is priced $4/$20 with $0.20/M cached input
- Grok 4.7's earlier $2/$6 undercut now only matches GPT-6 Sol on input
- Top tier: Claude Fable 5.1 and GPT-6 Astra both at $10/$50
GPT-5.6 was also due a scheduled 25% price increase in November, making GPT-6 effectively half of even the promotional pricing. Willison also compares pelican-drawing quality across model families at different reasoning levels.
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