No Deposit Bonus
A no deposit bonus gives you a small amount of free money or free spins when you register at a casino, without requiring you to deposit anything. Typical amounts range from $5 to $25 in bonus cash, or 10 to 50 free spins on a specific slot.
Before you get excited, read the conditions. No deposit bonuses almost always come with high wagering requirements (40x to 99x is common), a maximum cashout cap ($50 to $100 typically), and game restrictions. A $10 no deposit bonus with 60x wagering means you need to bet $600 before withdrawing, and even then you might only be allowed to cash out $100 maximum.
Are they worth claiming? As a way to test a casino with zero risk, yes. As a realistic way to make money, almost never. Treat them as a free trial, not a profit opportunity. If you happen to win something after clearing the wagering, consider it a pleasant surprise, not an expectation.