Anthropic and OpenAI trade price cuts with Opus 5.5 and the GPT-6 Sol and Luna models

On September 22, 2026, Anthropic shipped Claude Opus 5.5 with a 20% price cut, and OpenAI answered minutes later with two GPT-6 models, Sol and Luna, priced at half their predecessors. Model choice is now a budget decision as much as a technical one: benchmark cost per token against your real workload.