In Animal Farm what do the pigs sell?

The Pigs eat: The best of the animals crops and food, (cabbage, rice etc) and they also consume human food. A good way into the novel they also take up cider - which they sacrafice a whole field for, and spend money and time restoring the machinery to prepare the barley for fermentation. They tell the animals that they get the best of the food (for their brainpower - so they are able to run the farm).