Donating money to a charity is a fairly straightforward business, but you do need to keep careful records so you can document your donations at tax time. Never give cash—always use a credit card or write a check, and make the check out to the charity, not to an individual. For donations under $250, a canceled check is generally all the documentation you will need. However, for single donations of $250 or more, you must obtain a contemporaneous written acknowledgment of the gift from the charity. (Generally, if you were to make three separate donations to the same charity throughout the year totaling $250, you would not need a receipt—just your canceled checks.)