You can buy it at fair market value. Absent something like fraud, mistake or misrepresentation by the charity, which does not sound applicable to your situation, donors to charity cannot get their property back after they have given it. Unfortunately many donors, especially those considering gifts of real estate, don’t always consider this before they make the gift. Once a charity receives a gift, it must use it (or the proceeds from selling it) for its charitable purposes. The ministry could not give it to you, or sell it to you below fair market value, without creating an excess benefit transaction, on which you would be personally subject to tax. (See Ready Reference Page: “Charities Must Avoid Excess Benefit Transactions”)