The Item Inventory extension for GetPaid allows you to set stock levels for individual items.
Item’s with stock levels can be set to show when inventory is running low or out of stock. Additionally, emails are sent to notify you of low or out-of-stock items.
Back orders can be allowed OR can be set to prevent over-ordering. If a customer tries to order more items than you have in stock, a warning will show and the order will be prevented.
Requires the core GetPaid plugin