If any one item is worth more than $5000 you must have a written qualified appraisal done before the donation is done. This must be attached to the return when filed. For a vehicle the charity will provide you with a form showing what they got for the vehicle when sold. Your donation is the lesser of your basis, the fair market value at time of donation, or what the charity got for the vehicle. For any of these types of donations you must also get a contemporary letter from the charity showing the date of the donation, a description of the property, and a statement showing what if anything (or nothing) you received in return for the donation.