Create a unit economics model template for {{target_audience}} in the {{industry}} industry with a {{tone}} tone, designed for a {{business_model}} business model. Include formulas for: Customer Acquisition Cost (CAC), Lifetime Value (LTV), Gross Margin, Payback Period, LTV:CAC Ratio, and Churn Rate Impact. Each formula must be in a code block with variable definitions and realistic industry examples. Maximum 500 words.