ewich

This plugin came out of a use-case of a shop owner running a hybrid online and brick-and-mortar store, needing greater 
control of restrictions on selling products online. Imagine a local customer calls in and asks you to set aside a copy of a 
new board game, and you want to make sure that they don’t all sell online. Or, you’re pushing a hot new release and want to deter 
scalping bots and/or wholesale buyers from buying more than a handful of a certain product per transaction.
Enter Restrict Stock for WooCommerce – a very small, simple, and lightweight plugin that gives greater control over how the stock of your 
products are displayed and interacted with in the checkout process. Upon installation, a new group of new fields 
will be added to the Product > Inventory interface for all products called “Quantity to restrict,” “Restriction Notes,” and “Quantity to Hide.” 
Please see below for more information on these fields, and how they influence product stock and customers’ user experience.
<pre><code>- **Quantity to Restrict:** If you wish to only allow a certain number of this product to be purchased per transaction, enter it here
- **Restriction Notes:** If you are restricting amounts of this product per transaction, you can enter a custom error message here for when customers attempt to purchase more
- **Quantity to Hide:** If you are reserving, or hiding, a certain number of product from being displayed in stock counts and being sold, enter that number here
</code></pre>

Restrict Stock for WooCommerce

A basic plugin that can enforce quantity limits for products in WooCommerce Orders.

wpgear

The plugin makes it possible to sell Products as whole or in parts: 0.5 1.5 etc. 
(Piece of Product). Min, Max, Step & Default preset Quantity. Variable Products Supported.
For example: 
 Pizza. You can sell 1.5 Pizzas, or a quarter. With the price set for 1 piece. 
 Liquids on tap. For example, Kerosene or Olive Oil. You can sell 1.5 liters, with the price set for 1 liter. 
 Bulk materials. For example, Tobacco or Golden Sand. You can sell 0.1 g at a price quoted for 1 g.
<h4>Futured</h4>
<ul>
<li>You can set the Minimum product Quantity for all Products by default (preset = 1). But at the same time, each Product / Categories can have its own Minimum Quantity value.</li>
<li>You can set the Step of Changing the Quantity of goods for all Products by default (preset = 1). But at the same time, each Product / Categories can have its own value for the Change in Quantity Step.</li>
<li>You can set the Default – Choice product quantity for all Products by default (preset = 1). But at the same time, each Product / Categories can have its own Default – Choice Quantity value. </li>
<li>You can set the Maximum product Quantity for all Products by default. But at the same time, each Product / Categories can have its own Maximum Quantity value.</li>
<li>Works correctly with Variable Products.</li>
<li>Auto correction “No valid value” customer enters to nearest valid value.</li>
<li>Auto correction considering with “Maximum allowed for Product”.</li>
<li>Column “Quantity” on Products List.</li>
<li>Update Cart Automatically on Quantity Change (AJAX Cart Update)</li>
<li>You can set a “Value Label” for each individual Item. Individually or as a whole for the Category. For example: “Price per Meter”, “Price per Liter”.</li>
<li>It is possible to use Product – JS Object for Ext.Integration: QNT_Data. Function: WDPQ_Get_QuantityData (Product_ID).</li>
<li>Works with WooCommerce specifics from v3.4.8 & more</li>
<li>
Buttons: +/- To select the Quantity on the Product page and in the Cart.
<a href="http://wpgear.xyz/decimal-product-quantity-woo-pro/" rel="nofollow ugc">PRO Version</a> Features:
</li>
<li>You can set separate Minimum Product Quantity, Step of Changing the Quantity & Default preset Quantity – for each Variable Product Variation.</li>
<li>You can create RSS Feed for WooCommerce. Support: “Google Merchant Center” (Product data specification) for “Price_Unit_Label” -> [unit_pricing_measure], separate hierarchy Categories -> Products.</li>
</ul>

Decimal Product Quantity for WooCommerce

Products like: Pizza, Liquid on the filling, Custom weight, etc. (Piece of Product). Min, Max, Step & Default preset Quantity. Variable Supported.

Restrict Stock for WooCommerce vs Decimal Product Quantity for WooCommerce