An Item should not be duplicated if the purchase price of the item is different each time.
The purchase rate of the item can vary each time I procure that. Instead of creating a duplicate entry for the same item there should be provision of adding a different purchase price to the item already created. While tracking the particular item I should get a breakup of stock as how much quantity I purchased and at what price. It is becoming difficult as there are multiple entries of the same product.
You have an option to create a purchase price list in Zoho Inventory where you can associate multiple Purchase prices to the item.
Kindly follow this link to know more about the Purchase price list.
You can see the purchase details of this item in the respective Bills under the transactions options. Please refer to this link to know more about the purchase transactions against an item.