Robin Owns an Appliance Store

Essay

Robin owns an appliance store. Robin gives Tim a stereo unit to paint the front of her store building. The stereo unit, included in Robin's inventory at a cost of $400, normally retails for $700. If Tim had billed Robin for his work like he charged other customers, he would have sent Robin a bill for $600. Does Tim have income from the receipt of the stereo unit? If so, what amount should Tim report as gross income? Explain in terms of the Income Tax Concepts.