The cheapest LLM is a different model for every job (2026)

1Key Takeaways

• "What's the cheapest LLM right now?" is the wrong question.
• There isn't one cheapest model — there's a cheapest model for your workload , and it changes depending on what you're actually doing.
• The reason is simple once you see it: your bill is input_tokens × input_price + output_tokens × output_price .
• A chatbot, a RAG pipeline, a coding agent and a summarizer have wildly different input-to-output ratios, and some jobs won't even run on the cheapest model because it can't fit the context.