<form action="https://www.paypal.com/cgi-bin/webscr" method="post"> 
<input type="hidden" name="cmd" value="_xclick"><input type="hidden"
name="business" value="<paypalemail>">

<input type="hidden" name="item_name" value="Product name">

<input type="hidden" name="item_number" value="itemnumber">

<input type="hidden" name="amount" value="1.00"> 

<input type="hidden" name="return" value="http://www.yourdomain.com/returnURL.html">

<input type="hidden" name="cancel_return" value="http://www.yourdomain.com/">

<input type="image" src="https://www.paypal.com/images/x-click-but5.gif" border="0"
name="submit" alt="Make payments with PayPal - it's fast, free and
secure!"><input type="hidden" name="no_shipping" value="1"><input
type="hidden" name="undefined_quantity" value="0"><input type="hidden"
name="cn" value=""><input type="hidden" name="cs" value="0"></form>
