I tried to follow the product sense framework I've used for other interviews, but this question was actually not product related, it was budget related. When I tried to walk through the framework, the interviewer interrupted me. When I made assumptions that didn't fit with their expectations they impatiently corrected me. Overall I don't think the recruiter gave me good preparation for it because they don't set clear expectations: it could be case study (not even product focused), or behavioral, or "pick a product" style. Most companies tell you which of those three to prepare for and tell you what they're looking for in how you think. Stripe is vague and then tells you to google product sense and model their standards after facebook, which is a red flag. Their process is way too long and asks too much from candidates in my opinion.