https://tokencost.app/blog/gpt-4o-gpt-4-1-retirement-migration-cost TokenCost en 2026-10-16T00:00:00.000Z GPT-4o and GPT-4.1 retire January 14, GPT-4.1 nano in a week: what moving to GPT-6 Luna costs https://tokencost.app/blog/gpt-6-1-sol-ultrafast-pricing TokenCost en 2026-10-15T00:00:00.000Z GPT-6.1 Sol Ultrafast pricing: $12 in, $60 out, and more per token than GPT-6 Astra