I am using woocommerce 9.1.2 , I created a plugin to change the prices of the products while they are in the cart and complete the order; This is my code:

add_action('woocommerce_before_calculate_totals', 'custom_change_cart_item_price', 20, 1);
function custom_change_cart_item_price($cart) {

  if (is_admin() && !defined('DOING_AJAX')) return;

  foreach ($cart->get_cart() as $cart_item_key => $cart_item) {
           $new_price = $cart_item['data']->get_price() * 3;
           $cart_item['data']->set_price($new_price); 
  }
}

My wordpress version is 6.6

I have no errors or warnings in the debug.log; The goal is to temporarily change the prices in a certain context and have the customer complete the order with those prices, without changing the real price of the product

best regards,

For change price visibile in cart I use this:

add_filter('woocommerce_cart_item_price', 'custom_display_cart_item_price', 10, 3);
function custom_display_cart_item_price($price, $cart_item, $cart_item_key) {
    // Ottieni il prezzo regolare del prodotto
    $regular_price = $cart_item['data']->get_regular_price();

    // Verifica che il prezzo regolare sia stato recuperato
    if (!empty($regular_price)) {
        // Moltiplica il prezzo regolare per 3
        $new_price = $regular_price * 3;

        // Sovrascrivi il prezzo visualizzato
        $price = wc_price($new_price);
    }

    return $price;
}