gistfile1.txt

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

function big_apple_get_tax_class( $tax_class, $product ) {
	global $woocommerce;

	if ( $woocommerce->cart->subtotal <= 110 )
		$tax_class = 'Zero Rate';

	return $tax_class;
}