I built a fully autonomous AI agent that costs 0/monthtorun.Hereisexactlyhow.TheProblem:APIBillsAddUpWhenyoubuildanAIagent,thefirstthingyoureachforisanAPI:OpenAI,DeepSeek,Groq.Theyworkgreat—untilyoucheckthebill.Evenat0/month to run. Here is exactly how. The Problem: API Bills Add Up When you build an AI agent, the first thing you reach for is an API: OpenAI, DeepSeek, Groq. They work great — until you check the bill. Even at 0.14/million tokens, a moderately active agent burns through $30-50/month. That is a GPU you will never save up for. The second problem: most conversations do not need a frontier model . When a customer asks "How much is wedding photograph