Contributions to charity are an itemized deduction. You cannot claim itemized deductions in TurboTax Free Edition.
Because contributions to charity are an itemized deduction, the contribution will not make any difference in your tax unless your total itemized deductions are more than your standard deduction.
If you upgrade to TurboTax Deluxe and you want to enter contributions to charity, type "donations" (without the quotes) in the Search box, then click the link that says "Jump to donations." You do not enter the tax ID of the organization. For donations of money, all you have to enter is the name of the organization and the amount. You do not need a receipt from the organization for a contribution of less than $250, but you have to have a canceled check, credit card statement, or other record showing the contribution. You keep that with your tax records in case the IRS questions the deduction. You do not include it with your tax return.