Deductions for product reviews? Have I found a loophole?

I own a number of websites and some of them do product reviews.

If I buy a product to do a review on I can deduct that correct? After I am done with the review what can I do with the product?

Can I sell the product to myself (from the corporation) or a friend for one dollar? If so can I do a review about every single product I buy, like a car or TV?

I would guess that this is illegal in some way but have not found any documentation.