woocommerce_before_calculate_totals

 foreach ($cart->get_cart() as $cart_item) {
            
            
            if (isset($cart_item['fooevent_class_date'])) {
                
                $product = $cart_item['data'];
                $product_id = $cart_item['variation_id'] > 0 ? $cart_item['variation_id'] : $cart_item['product_id'];
                
                $eventtype=get_post_meta($product_id, "WooCommerceEventsType", true);
                
                if(is_user_logged_in() && $eventtype == 'sequential'){
                    
                     $roles = wp_get_current_user()->roles;  
                     
                    if(in_array('subscriber',$roles)){ 
                        
                     $custom_price = (float) number_format(0, wc_get_price_decimals(), '.', '');
                     
                     method_exists( $product, 'set_price' ) ? $product->set_price( $custom_price ) : $product->price = $custom_price; 
                        
                        
                    }
                    
                  
                }

                
            }
        }