Rebates from a dealer or manufacturer for items you purchase are tax free. They are viewed in the tax law as merely reducing the purchase price of the item.
Example: A rebate you receive from a dealer or manufacturer of an item you buy is not income, but you must reduce your basis by the amount of the rebate. IE. You buy a new car for $9,000 cash and receive a $400 rebate check from the manufacturer. The $400 is not income to you. Your basis in the car is $8,600. This is your basis on which you figure gain or loss if you sell the car, and depreciation if you use it for business.