Yummy.eu, a Lean-ops meal-kit company, initially used SaaS ETL tools but faced high costs and performance issues. To address these concerns, they shifted to using Python dlt, which significantly improved data processing speed and reduced costs by 182 times compared to their traditional tool. This change enabled Yummy to regain control over their data management processes and budget, showcasing the potential of open-source tools in simplifying data operations and achieving cost-effectiveness.