Get X post tags

Your question seems similar to this one:
how to limit and display tag?

Based on it you can use this code to limit the tags:

$post_tags = get_the_tags();
   shuffle($post_tags); // use this incase you want to pick the tags randomly
   $count = 0;
   if ($post_tags) {
       foreach($post_tags as $tag) {
          $count++;
          echo '<a href="'.get_tag_link($tag->term_id).'">'.$tag->name.'</a> ';
          if( $count > 4 ) break;
       }
   }

It will return 3 tags only.