Prototyping for revenue streams involves three main steps: exploring, evaluating, and refining. To explore, you can brainstorm and research potential revenue streams, utilizing tools like the Business Model Canvas or the Lean Canvas to map out your value proposition, customer segments, and revenue streams. Additionally, you can look at competitors, benchmarks, and best practices to gain inspiration and insights. Evaluating requires testing and validating your revenue streams with your target customers through prototyping. You can create prototypes simulating different pricing models, payment methods, or value propositions in order to gauge customer feedback. Surveys, interviews, or landing pages can also be used to measure their willingness to pay, price sensitivity, or conversion rates. Finally, refining is the step where you analyze and improve your revenue streams based on the feedback and data collected from prototyping. The Lean Startup Method or the Build-Measure-Learn cycle are great tools for iterating and optimizing your revenue streams based on customer feedback, metrics, and experiments.