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 down 20% to $2/$12. GPT-5.6 Sol gains a Fast API mode with 2.5x speed at 2x price. OpenAI credits Sol's self-optimization for 20% lower serving costs.