Learn the details about how to display the sale price before the regular price in WooCommerce.
Use below snippet code to display the sale price before the regular price. Add this code in active theme function.php.
add_filter( 'woocommerce_format_sale_price', 'invert_sale_price_format', 10, 3 );
function invert_sale_price_format( $price, $regular_price, $sale_price ) {
return '<ins>' . ( is_numeric( $sale_price ) ? wc_price( $sale_price ) : $sale_price ) . '</ins> <del>' . ( is_numeric( $regular_price ) ? wc_price( $regular_price ) : $regular_price ) . '</del>';
}