This snippet checks to see if a WooCommerce product is a member of a specific category, upon which a unique Tax class is conditionally applied

cjws-wc-conditional-sales-tax

/**
* CJWS: WC Conditional Tax Class
*
* Provides conditional *tax classes* based on product category
* May be adapted to consider other criteria, such as post type
* Modifies 'woocommerce_product_tax_class' filter 
* 
*@author CJ Andrew <[email protected]>
*
*@since 1.0
*
*@param mixed $tax_class
*@param mixed $product
*
*/

function cjws_wc_conditional_sales_tax($tax_class, $product){
  
    if( is_checkout() && is_product_category('tickets')){
      $tax_class = 'Special Rate';
    }
    
    return $tax_class;
}

add_filter('woocommerce_product_tax_class', 'wc_diff_rate_for_user', 1,2);