Slot tournaments are the most common format (but you’ll also find blackjack cashback deals), leaderboard challenges, and prize drops on specific games. Once your friend signs up and makes a qualifying deposit — usually around $50 — you’ll receive a bonus, either in cash or free spins. Refer-a-friend bonuses are a fairly common feature at online casinos, rewarding you for introducing friends to a site you already use. (more…)