Custom fields in logical order

Im Trying to get custom fields to work in a flow of logic below

If author do nothing

If not

Check price? if price show price and tag

if not

Check reviewazon price? if price

show reviewazon price and tag

If not

Show out of stock banner.

This is my code so far,

<?php if(get_post_meta($post->ID, 'Authors', true) == '') { ?>

			<?php $price = get_post_meta($post->ID, 'price', true);
			 if ( $price ) {
 echo '<span class="price-tag">	';
		}
else {
echo '<span class="band2 outofstock2"></span>';
}
?>	

			<?php if(get_post_meta($post->ID, 'price', true) != "") { ?>
<span><?php echo $Price = get_post_meta($post->ID, 'price', true); ?></span>
<?php } ?>

<?php } ?>

And anyone help get me what I want? I’ve whacking my brains for days