Simple custom shortcode problem

I have the following custom shortcode code which I put into my theme functions.php file (I was given this code). It is just to help me get a list of product names with a cost for every product under a specific category. Example: PRODUCT NAME $X.XX. Each product would be on a new line. This is working out fine, but when I use the short code to put this on a page, I put the shortcode UNDER text I want on the page, but the shortcode ALWAYS shows it ABOVE the text rather than UNDER which is where I put the shortcode and expected the out put to be?

I also found that it doesn’t show the currency symbol, but shows USD instead?

function product_list_by_category_name( $product_category_name ){
	$args = array( 'post_type' => 'product', 'product_cat' => $product_category_name );

    $loop = new WP_Query( $args );

    while ( $loop->have_posts() ) : $loop->the_post();
    global $product; 

	$amount = get_post_meta($product->post->ID, '_price', true) . ' ' . get_woocommerce_currency();

	echo '<a href="'.get_permalink().'">'. get_the_title() .'</a> '. $amount .'<br />';

    endwhile; 

    wp_reset_query();
}

/** SHORTCODE **/
function product_list_by_category_name_shortcode( $atts ) {
	extract(shortcode_atts(array(
		'product_category_slug' => ''
	), $atts));

	return product_list_by_category_name( $product_category_slug );
}

add_shortcode( 'product_list_by_category', 'product_list_by_category_name_shortcode' );

https://wordpress.org/plugins/woocommerce/