Change Price Once Specific Number of Items Sold in WooCommerce

This code alters the price per product once a specific number of stock have been purchased or inventory level reached in WooCommerce.

The code includes variables you can use to set :

• The specific product id
• Sales or stock inventory threshold
• New regular price

This solution works based on total sales of the product once the order status has completed.

add_action('woocommerce_order_status_completed', 'update_product_price_based_on_sales');
function update_product_price_based_on_sales( $order_id ) {

    $product_id = 888; 
    $sales_threshold = 100; 
    $new_price = 50; 

    $product = wc_get_product($product_id);
    
    $total_sales = (int) get_post_meta( $product_id, 'total_sales', true );

    if ( $total_sales >= $sales_threshold ) {
    
        $product->set_regular_price($new_price);
        
        $product->save();
        
    }
}

You can also change the price based on inventory levels rather than sales using this code :

add_action('woocommerce_product_set_stock', 'update_product_price_based_on_stock');
function update_product_price_based_on_stock($product) {

    $product_id = 888; 
    $stock_threshold = 100; 
    $new_price = 50; 

    if  ($product->get_id() === $product_id ) {
    
        $current_stock = $product->get_stock_quantity();

        if ( $current_stock <= $stock_threshold ) {
        
            $product->set_regular_price($new_price);
            
            $product->save();
            
        }
    }
}

All custom function should be added to a child theme functions file or custom code snippets plugin.