I managed to figure it out. So here’s the solution. Go to plugin\templates\print\print-delivery-note.php find <table> around line 62
<table>
<thead>
<tr>
<th class="product-label"><?php _e('Product', 'woocommerce-delivery-notes'); ?></th>
<th>U.M</th>
<th class="quantity-label"><?php _e('Cantitatea', 'woocommerce-delivery-notes'); ?></th>
<th class="totals-label"><?php _e('Pretul Unitar -lei-', 'woocommerce-delivery-notes'); ?></th> // this is the single price table heading
<th class="totals-label"><?php _e('Valoarea -lei-', 'woocommerce-delivery-notes'); ?></th>
</tr>
</thead>
<tbody>
<?php $items = wcdn_get_order_items(); if( sizeof( $items ) > 0 ) : foreach( $items as $item ) : ?><tr>
<td class="description"><?php echo $item['name']; ?>
<?php echo $item['meta']; ?>
<dl class="meta">
<?php if( !empty( $item['sku'] ) ) : ?><dt><?php _e( 'SKU:', 'woocommerce-delivery-notes' ); ?></dt><dd><?php echo $item['sku']; ?></dd><?php endif; ?>
<?php if( !empty( $item['weight'] ) ) : ?><dt><?php _e( 'Weight:', 'woocommerce-delivery-notes' ); ?></dt><dd><?php echo $item['weight']; ?><?php echo get_option('woocommerce_weight_unit'); ?></dd><?php endif; ?>
</dl>
</td>
<td>BUC.</td>
<td class="quantity"><?php echo $item['quantity']; ?></td>
<td class="price"><?php echo $item['single_price']; ?></td> // this adds the single price for item
<td class="price"><?php echo $item['price']; ?></td>
</tr><?php endforeach; endif; ?>
</tbody>
</table>