WooCommerce Change Free price text

gistfile1.php

// Change free price text
function custom_free_price( $price, $product ) {
	return '';
}
add_filter( 'woocommerce_free_sale_price_html', 'custom_free_price', 10, 2 );
add_filter( 'woocommerce_free_price_html', 'custom_free_price', 10, 2 );
add_filter( 'woocommerce_variable_free_price_html', 'custom_free_price', 10, 2 );
add_filter( 'woocommerce_variable_free_sale_price_html', 'custom_free_price', 10, 2 );