Build an AI agent expense tracker in n8n that logs and analyzes your spending from a simple chat message. Just type "Spent $12 on lunch" and the agent records it in Google Sheets. Ask "How much did I spend on food this month?" and it calculates the answer for you. In this step-by-step n8n tutorial, you'll build an AI-powered expense tracking workflow using Google Gemini, memory, a calculator tool, and Google Sheets tools. No coding is required.