Add a fee to WooCommerce per product, based on category

I was having the same issue and came across a code snippet that set me on the correct path. For the life of me, I cannot find the original site that housed the snippet, but here is my reworked version.

function df_add_ticket_surcharge( $cart_object ) {

    global $woocommerce;
    $specialfeecat = 86; // category id for the special fee
    $spfee = 0.00; // initialize special fee
    $spfeeperprod = 0.05; //special fee per product

    foreach ( $cart_object->cart_contents as $key => $value ) {

        $proid = $value['product_id']; //get the product id from cart
        $quantiy = $value['quantity']; //get quantity from cart
        $itmprice = $value['data']->price; //get product price

        $terms = get_the_terms( $proid, 'product_cat' ); //get taxonamy of the prducts
        if ( $terms && ! is_wp_error( $terms ) ) :
            foreach ( $terms as $term ) {
                $catid = $term->term_id;
                if($specialfeecat == $catid ) {
                    $spfee = $spfee + $itmprice * $quantiy * $spfeeperprod;
                }
            }
        endif;  
    }

    if($spfee > 0 ) {

        $woocommerce->cart->add_fee( 'Ticket Concierge Charge', $spfee, true, 'standard' );
    }

}

add_action( 'woocommerce_cart_calculate_fees', 'df_add_ticket_surcharge' );

This will add a 5% surcharge to each item in the cart with the category of ticket (id: 86). I hope this helps you out, if you have not found a solution already.

thanks for posting this above code. I had needed exactly this, but there were some problems for, me. I didn't want the category to be a part of it, i wanted it to apply to all products, and I also required a fixed fee per product.

The other problem I had was if I had 2 different products in the cart it would only calculate it as 1 product. so I did some research and found a way for it to calculate the total number of products in the cart. So here is the final code I came out with. Thought it may help someone else looking for a similar answer

/** add handling fee **/
function df_add_handling_fee( $cart_object ) {

global $woocommerce;
// $specialfeecat = 3711; // category id for the special fee
$spfee = 0.00; // initialize special fee
$spfeeperprod = 10; //special fee per product

//Getting Cart Contents. 
$cart = $woocommerce->cart->get_cart();
//Calculating Quantity
foreach($cart as $cart_val => $cid){
   $qty += $cid['quantity']; 
}
foreach ( $cart_object->cart_contents as $key => $value ) {

    $proid = $value['product_id']; //get the product id from cart
    //$quantiy = $value['quantity']; //get quantity from cart
    $itmprice = $value['data']->price; //get product price

    $terms = get_the_terms( $proid, 'product_cat' ); //get taxonamy of the prducts
    if ( $terms && ! is_wp_error( $terms ) ) :
        foreach ( $terms as $term ) {
            //$catid = $term->term_id;
            //if($specialfeecat == $catid ) {
                $spfee = $qty * $spfeeperprod;
            //}
        }
    endif;  
}

if($spfee > 0 ) {

    $woocommerce->cart->add_fee( 'Handling Fee', $spfee, true, 'standard' );
}

}

add_action( 'woocommerce_cart_calculate_fees', 'df_add_handling_fee' );

As you can see I have just commented out the parts from the original code. Hope someone can benefit from this :)