FatCamera/Getty Images A cashier's check is a type of bank-issued check; the bank itself guarantees that the funds will be available when the check is cashed. Cashier's checks are especially useful for large transactions, like buying a house or a car, where other forms of payment may be unacceptable. Most banks and credit unions offer cashier's checks, but some will only issue them to their own customers. Click here to learn more or sign up for a Betterment checking account » If you decide to pay someone with a check, you have three main options: personal checks, certified checks, and cashier's checks.