Schools, libraries, and other organizations often ask you to make a nominal donation to their cause. While you want to support many causes, these nominal donations soon add up to a substantial portion of your budget!
Another meaning for the adjective nominal is "in name only" or only having a title. The CEO is the nominal head of the company, but you know his assistant is one who is really in charge of the day-to-day business of the company. He is the go-to person for signing invoices, purchase orders, and resolving personnel issues.