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GPT-6 Sol and Luna ship at half their predecessors' prices
Sol goes from $4 / $20 to $2 / $10 per million tokens, Luna from $0.20 / $1.20 to $0.10 / $0.50, against GPT-5.6 promotional pricing.2 OpenAI attributes the cut to caching and inference improvements rather than a smaller model, and Astra remains the top of the family. Both are available now on the API and in the GitHub Copilot picker.6 The published prices are the part we can check; the benchmark tables beside them are OpenAI's own and are in Skip This below.
Relevant to: Anyone with a Sol or Luna line in a production bill, and anyone who priced an agent out at the old rate.
What the verdict meansAvailable, works, worth your time today.
The prices, side by side
- GPT-5.6 Sol $4 / $20 → GPT-6 Sol $2 / $10 per MTok.
- GPT-5.6 Luna $0.20 / $1.20 → GPT-6 Luna $0.10 / $0.50 per MTok.
- Claude Opus 5 $5 / $25 → Claude Opus 5.5 $4 / $20 per MTok.
- All six figures are from the vendors' own pages, read 23 September. The GPT-5.6 numbers are described by OpenAI as promotional pricing, so the comparison is against a promotion, not a list price.
Sources
Originally part of the 23 September 2026 edition.