The two key questions:
a) Did you make money on it?
b) Did anyone issue you a 1099-S tax form reporting the sale?
If the answer to both questions is "no" then you don't have to report the sale on your income tax if the mobile home was for personal use..
If you were renting it out and taking depreciation deductions when you reported the rental income then you would also need to report it on your tax return.