Stock/Inventory Control with Easy Books
Easy Books 6.0 for iOS and Easy Books 3.0 for Mac now support purchase and sale of stock items.
Using the new stock and services sections of the app, you can define your products, including the option to set quantity pricing so you can offer your customers a discount for volume purchases.
The app keeps track of the current quantity and value of your stock products and uses these to de-value the stock you are holding in your asset account as you make sales. It is possible to adjust stock too if you need to, just edit the product details and change the current qty and valuation.
Easy Books can manage devaluations for stock that you buy and later sell, but it doesn't do this for manufactured items. In the case where you purchase stock products for manufacturing into a new stock product which you sell yourself, it's possible but slightly more work.
For an example of how to handle this, please see the discussion: