A bonus bet (or "free bet") only pays if it wins — and usually the stake isn't returned, only the winnings. If it loses, you get nothing. That's the catch.
The trick: alongside the bonus bet on one outcome, you cover the other outcome(s) with real bets at other sportsbooks. Now:
- If the bonus bet wins → you collect the winnings, minus the small cost of the covering bets.
- If the bonus bet loses → your covering bet wins and pays you instead.
Either way you walk away with roughly ~70% of the bonus value as guaranteed cash (US bonus bets are stake-not-returned, so ~70% is the honest, structural figure — a bit more at longer odds). Do it across every welcome offer and ongoing promo, and it adds up fast.