To answer "What is first deposit bonus?", start with how the offer is built. A welcome offer is rarely one bonus. It is usually a package spread across several deposits, each with its own match percentage, ceiling and conditions, and sometimes with free spins attached. The headline adds the parts together, which makes the whole look larger than any single step. Taking the package apart shows what each deposit actually earns and what it asks in exchange.
Every offer names a qualifying deposit, a minimum below which no bonus is paid. Some also require a code at the cashier or a tick in an opt in box before the payment, and a deposit made without it rarely earns the bonus afterwards. Certain payment methods, often electronic wallets and prepaid cards, are excluded from welcome offers in the terms. Checking the method and the code before paying avoids a deposit that earns nothing at all.
Packages split across several deposits release each tier only after the previous one is claimed, and often only within a set number of days of registration. Later tiers tend to carry smaller percentages. Each tier normally has its own wagering requirement, and some casinos stack them, so an unfinished requirement from the first deposit blocks the second. Reading the tiers as separate offers, each with its own cost, shows which of them are worth claiming at all.
A match bonus adds a percentage of the deposit, up to a ceiling. A hundred percent match up to a stated maximum doubles a deposit that stays under the ceiling, and adds nothing to the part above it. Higher percentages usually come with lower ceilings or heavier wagering. Comparing offers by the bonus a planned deposit would actually receive, instead of the largest figure in the banner, keeps the comparison honest and often reverses the order of two competing offers.
Bonuses that return after the welcome package, often weekly, with smaller matches and the same kind of wagering attached.
Some offers only apply when a box is ticked before payment, and a deposit made without opting in usually earns nothing afterwards.
Every offer names a qualifying deposit, and a payment below that minimum earns no bonus at all.
A sticky bonus is removed at withdrawal, leaving only the winnings above it, while a cashable bonus joins the balance once wagering is met.