Last month I helped a friend cut his LLM API bill by 80%. He's a non-technical founder building an AI-powered business. Like most people, he picked GPT-5 because it's the default: You have the API already, it has solid benchmarks, everyone uses it, why bother?! But as usage grew, so did his bill. $1,500/month for API calls alone. So we benchmarked his actual prompts against 100+ models and quickly realized that while GPT-5 is a solid choice, it almost never is the cheapest and there are always c...