Business & farm

@Geraldine Painter Yes, when indicating that you stopped using your Vehicle for Business, you enter a 'sale price', which can be the amount you received as a Trade-In.

When you claim a Standard Mileage deduction, you are also claiming Depreciation.  Part of the per mile deduction is considered depreciation.

To figure your 'Accumulated Depreciation' you need to relate the Business Miles you claimed each year to to the Depreciation Equivalent Table to calculate the depreciation you have taken on your Business Vehicle.

If you have used your Business Vehicle over five years, it is fully depreciated, so you can just indicate that it was 'converted to personal use' and be done with it. 

If not, see page 24 of IRS Pub. 463 for your calculations  (screenshot). 

Since the vehicle was a gift, your 'Cost Basis' would be the Fair Market Value of the vehicle when you started using it for business. 

Click this link for more info on How to Close a Business on your Tax Return.