Basic slot machine game
Looks good. Few initial things:


Indent inside control structures, so everything inside your if() statement would be prefixed by one tab. (You can use a fixed number of spaces, but that can cause problems if you share your code with people who use a different tab-spacing system).
It is a really good idea to split out your code into logic (or "controller") and template (or "view"). Your html would then go in a different file and be loaded by your PHP file - a good first step with this sort of thing is Smarty. From there you can progress to a proper PHP framework such as Symfony or Zend (but be aware the learning curve is steep).
Tags such as &lt;center&gt; and &lt;big&gt; tend to be discouraged - use CSS instead.
Keep your PHP statements in your view as small as possible. For example I'd rewrite your score thus:



&lt;div class="points"&gt;
    You have &lt;strong&gt;&lt;?php echo $current ?&gt;&lt;/strong&gt; points!
&lt;/center&gt;



You'll need to define a CSS class called 'points', of course.