Can I make a fake PayPal donate button in the SandBox for testing?

Question 1

You need to register this page: https://developer.paypal.com/

Then you can use the paypal API like this:

<html>
<head>
<title>Test Page</title>
</head>
<body>

<p>This is a test HTML file.</p>

<form action="https://www.paypal.com/cgi-bin/webscr" method="post">

<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="encrypted" value="-----BEGIN PKCS7-----...[Encrypted message]...-----END PKCS7-----">

<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">

</form>

</body>
</html>

Question 2

Any emails sent within the sandbox system never go to an actual email. They only go to the Test Email tab within your developer.paypal.com account.

That said, you can always just create a new buyer or seller account, and use that one. You create the password when you create the account.

Question 3

Once you create your sandbox account, you can obtain the "fake" donation button from the sandbox paypal buttons url: https://www.sandbox.paypal.com/buttons/

Until we found this, we couldn't test the donation buttons.