GTM ClubCAC is what makes motions comparable: outbound costs people and tools, inbound costs content and time, product-led costs free users who never pay. Each produces a customer at a price, and the price decides which one a company can afford at its deal size.
The number that goes with it is payback: how many months of revenue it takes to earn CAC back. Outbound that costs €3,000 per customer is cheap at a €30,000 contract and ruinous at €500 a year.