Laszlo Kruchio

This plugin creates an input field on the single product page, if the product is out of stock under the summary. The user can enter an email address to subscribe for the product alert. 
This email address is saved to the database within a new table. If the product stock changed from out of stock, the user will get an email with a custom message. This message can be edited on the option page.
Warning: The plugin doesn’t work 100% with variable products.
<ul>
<li>Custom Email Sender / Subject / Email address</li>
<li>Custom Email Message with tags (%product_name%, %product_link%)</li>
<li>Custom Placeholder & Submit button value for the form</li>
<li>Custom Error / Success message</li>
<li>Disable default CSS</li>
<li>Use shortcode instead of the default form</li>
<li>List of subscribers with filters</li>
</ul>
Logo and Banner design by <a href="https://ie.linkedin.com/pub/andressa-lombardo/89/173/486" rel="nofollow ugc">Andressa Lombardo</a>

Instock Email Alert for Woocommerce

Simple, Clean and works perfect.

Handy plugin to create an input field if the product is out of stock. The user will be alerted with a custom email, when the product stock changed.

Paolo

AyeCode

Stiofan

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 <a href="https://wordpress.org/plugins/invoicing/" rel="ugc">GetPaid plugin</a>

GetPaid > Item Inventory

Set the inventory amount and never sell anything you don't have in stock.

Instock Email Alert for Woocommerce vs GetPaid > Item Inventory