What does building and running internal tools with AI actually cost compared to SaaS subscriptions?

Expect $20 to $200 a month in AI tooling (Lovable, Replit, or a Claude Code plan) plus a few dollars of hosting, against SaaS line items that commonly run hundreds per seat per year; Blinkist replaced roughly $60k a year of SaaS with two AI-built apps, and a 55-person property firm saved about $100k replacing Salesforce. The catch is post-launch: debugging, hosting, integrations, and eventual hardening often cost more than the build itself. Compare on maintenance hours, not just subscription prices.

A quick orientation. The real value is below: resources worth your time, from people who've actually done it.