Change cart item prices in Woocommerce 3 - php

Question

I am trying to change product price in cart using the following function:
add_action( 'woocommerce_before_shipping_calculator', 'add_custom_price'
);
function add_custom_price( $cart_object ) {
foreach ( $cart_object->cart_contents as $key => $value ) {
$value['data']->price = 400;
}
}
It was working correctly in WooCommerce version 2.6.x but not working anymore in version 3.0+
How can I make it work in WooCommerce Version 3.0+?
Thanks.

Answer 1

Update 2021 (Handling mini cart custom item price)
With WooCommerce version 3.0+ you need:
To use woocommerce_before_calculate_totals hook instead.
To use WC_Cart get_cart() method instead
To use WC_product set_price() method instead
Here is the code:
// Set custom cart item price
add_action( 'woocommerce_before_calculate_totals', 'add_custom_price', 1000, 1);
function add_custom_price( $cart ) {
// This is necessary for WC 3.0+
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
// Avoiding hook repetition (when using price calculations for example | optional)
if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
return;
// Loop through cart items
foreach ( $cart->get_cart() as $cart_item ) {
$cart_item['data']->set_price( 40 );
}
}
And for mini cart (update):
// Mini cart: Display custom price
add_filter( 'woocommerce_cart_item_price', 'filter_cart_item_price', 10, 3 );
function filter_cart_item_price( $price_html, $cart_item, $cart_item_key ) {
if( isset( $cart_item['custom_price'] ) ) {
$args = array( 'price' => 40 );
if ( WC()->cart->display_prices_including_tax() ) {
$product_price = wc_get_price_including_tax( $cart_item['data'], $args );
} else {
$product_price = wc_get_price_excluding_tax( $cart_item['data'], $args );
}
return wc_price( $product_price );
}
return $price_html;
}
Code goes in functions.php file of your active child theme (or active theme).
This code is tested and works (still works on WooCommerce 5.1.x).
Note: you can increase the hook priority from 20 to 1000 (or even 2000) when using some few specific plugins or others customizations.
Related:
Set cart item price from a hidden input field custom price in Woocommerce 3
Change cart item prices based on custom cart item data in Woocommerce
Set a specific product price conditionally on Woocommerce single product page & cart
Add a select field that will change price in Woocommerce simple products

Answer 2

With WooCommerce version 3.2.6, #LoicTheAztec's answer works for me if I increase the priority to 1000.
add_action( 'woocommerce_before_calculate_totals', 'add_custom_price', 1000, 1);
I tried priority values of 10,99 and 999 but the price and total in my cart did not change (even though I was able to confirm with get_price() that set_price() had actually set the price of the item.
I have a custom hook that adds a fee to my cart and I'm using a 3rd party plugin that adds product attributes. I suspect that these WooCommerce "add-ons" introduce delays that require me to delay my custom action.