On an item, what is the difference between inventory units and price units?

Inventory units of measure (i.e., UOM's) are the measure by which items are maintained in inventory. Price units, on the other hand, are the measure for items when they are sold. A single item may have different inventory and price units. Having two different units would apply if you sell items in different units than you stock them in. For example, if you are a beer distributor, you might stock beer in pallets but sell beer in cases. In this example, your inventory unit would be PALLET and your price unit would be CASE.