<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="business" value="hide@address.com">
<input type="hidden" name="undefined_quantity" value="1">
<input type="hidden" name="item_name" value="100 tickets">
<input type="hidden" name="item_number" value="agbp1day">
<input type="hidden" name="amount" value="50.00">
<input type="hidden" name="no_shipping" value="1">
<input type="hidden" name="no_note" value="1">
<input type="hidden" name="currency_code" value="EUR">
<input type="hidden" name="bn" value="PP-BuyNowBF">
<input type="image" src="https://www.sandbox.paypal.com/en_US/i/btn/x-click-but23.gif" border="0" name="submit" alt="Make payments with PayPal - it's fast, free and secure!">
</form>