Shipping for first item of category, only

In my webshop I have free shipping as default.

Now I want to introduce a new category of articles and I want the buyer to pay a fixed shipping fee whenever he buys one or more items of this category.

I also have a fast shipping fee. When buyers choose it they pay a fixed amount, regardless of the quantity of products.

So, I want the shipping to remain free for all categories but this new one, and I want the buyer to pay the same fee regardless of the quantity of products, unless he chooses the fast delivery shipping, where he'll pay a different value.

How can I go about this?

If I understand correctly, you can clone the table rate for your "fast" ship that can be selected. Your "free ship" items remain free and your others are not marked as free ship when you create them

OK. How do I clone the table rate?

Search for it!!

http://www.zen-cart.com/forum/showthread.php?t=69665

Sorry, I tried it and this is not what I need. Maybe I wasn't clear.

What I need is for the first ordered item of a certain category to have a default shipping cost. But then the following items won't have shipping cost. This way the buyer pays the same shipping cost regardless of the number of items he buys.
But I want this to happen on one category of products, not all. So, it must not be a shipping option, but a characteristic of the product category.

What shipping method(s) do you use for all other Products/Categories on your site?

For all products I have free shipping and Express delivery via TNT.

In this case the shipping must not be optional, it must cost 5€ for the first item of the category.

You could just test the cart and if 1 or more products from that category is in the cart you can add $5.00 to the cost ...

What specific Shipping module is managing the Free Shipping?

I have no idea what the TNT shipping is that you are using for the Express, but the idea is probably the same ...

The free shipping is done by "free options", and the TNT (courier) is done by "Flat Rate Clone".

So, how do I test the cart and add 5€ if a certain product or category is there?

If you do not use Linked Products, then you can test if a Product from a particular categories_id is in the shopping_cart by test the master_categories_id ...

There is a function in the shopping_cart class for testing things like this:

  /**
   * Method to calculate the number of items in a cart based on an abitrary property
   *
   * $check_what is the fieldname example: 'products_is_free'
   * $check_value is the value being tested for - default is 1
   * Syntax: $_SESSION['cart']->in_cart_check('product_is_free','1');
   *
   * @param string product field to check
   * @param mixed value to check for
   * @return integer number of items matching restraint
   */
  function in_cart_check($check_what, $check_value='1') {