A €2 referral can still lose money.
A payout is not revenue until you multiply it by the people who actually make it through acceptance.
Suppose a referral programme pays €2 per confirmed referral. If 60% of raw signups are accepted, each raw signup is worth €1.20 in expected revenue:
Raise the acquisition cost to €1.30 and the same funnel loses €0.10 per raw signup. At 100 signups, that is a €10 loss before creative, tools, time, refunds, or tax enter the picture.
Before fixed costs, the break-even acquisition cost is the expected revenue per raw signup: payout × acceptance rate. Treat that as a ceiling to test against, not a promise. Geography, screening, engagement, budget, and the details of an offer can all change the acceptance rate.
For terminology and programme mechanics, see SparkLoop’s referral channels guide and paid recommendation budgets guide. This worked example is hypothetical; it is not a SparkLoop offer or a guarantee of economics.