OpenAI cuts GPT-5.6 Luna price 80%, Terra 20%

GPT-5.6 Luna now costs $0.20 per million input tokens and $1.20 per million output, an 80% drop; Terra is 20% cheaper at $2/$12. GPT-5.6 Sol gains a Fast mode in the API: 2.5x speed for 2x price. OpenAI credits Sol with optimizing inference, cutting serving costs by 20%.