I'm not a CPA but if you are ACTUALLY running a rental car company and ACTUALLY renting out the Lamborghini, you should be able to write off the depreciation and treat the purchase as a cost. You will have a harder time convincing the IRS that you need a Lamborghini with an ad on it to successfully run your business and that it's a true business expense if you're just going to be driving it around for personal use. I would think you could deduct the cost of putting the ad on the car but not the car itself.