"If we self-host Matomo or Umami, the revenue dashboard is free, right?" That's one of the most common questions I hear from SMB EC operators in Japan. The short answer: license-fee-free is not TCO-free . After laying four options side-by-side at Japanese freelance rates, self-hosted dashboards land at ¥460K-880K per year — 4-7x the cost of a focused SaaS like the one I'm building. I've been building RevenueScope for the Japan SMB EC market, so I have a stake in this comparison. But the math here is structural, not promotional: when you account for build hours, ongoing ops, server costs, and learning curve, "free" OSS quietly becomes one of the most expensive choices on the table. This post walks through the TCO breakdown, the three hidden cost layers most operators miss, and a 3-question framework that decides between self-hosted and SaaS in about 60 seconds.…