Building billing and pricing systems can be complex, filled with jargon that can be overwhelming for those new to the field. To assist in navigating this landscape, the text provides an extensive glossary of terms and concepts crucial for such systems, including coupons, billable metrics, credit notes, and various pricing models like freemium, usage-based, and dynamic pricing. It highlights the importance of understanding use cases, considerations, and potential risks associated with each concept to ensure accurate billing, customer satisfaction, and effective revenue management. The text also underscores the significance of metrics like ARR, MRR, and NRR for financial forecasting and strategic planning, emphasizing the need for clarity, transparency, and automation in managing these systems to optimize business outcomes and enhance customer relationships.