The Mechanics
A $200 bonus with 10x rollover requires $2,000 in qualifying bets before withdrawal. Each bet loses roughly the vig (~4.5% at -110), so clearing costs about $90 in expected losses — nearly half the bonus. The formula: expected clearing cost = rollover volume × house edge per bet.
The Traps
Watch for: rollover applying to deposit + bonus (doubling the volume), minimum odds forcing you into specific bet types, maximum bet caps while clearing, short expiry windows, and games/markets contributing at reduced rates. Casino-style 30-40x requirements on 'free' sports credits are effectively unclearable.
A Quick Value Test
Real bonus value ≈ face value − (total required volume × house edge). If that number is under a third of the headline amount, skip the offer. Clean low-rollover bonus-bet offers from major regulated books usually score best on this math.