How do I track repeat purchase rates for discount customers?

As an e-commerce manager, I'm struggling to understand how discount-driven customers behave beyond their initial purchase. I want to develop a comprehensive strategy for tracking repeat purchase rates specifically for customers who first converted through a promotional offer. My goal is to determine whether these customers become long-term, loyal buyers or if they're just one-time discount hunters. I need a systematic approach to measure customer lifetime value, segment these customers, and design retention strategies that transform discount-motivated buyers into repeat customers.