Extension:MiniDonation

The MiniDonation extension adds parser hook which can be used to display a PayPal donation form on a page. It's Wikimedia-specific so you need to edit the  file to make the extension suit your needs.

Adaptation
If you want to completely change the form then:
 * 1) Edit
 * 2) Get rid of everything between   and  
 * 3) Replace it with your HTML (e.g. the HTML from paypal.com when you create a button there)

If you use and nothing appears after the donation form on your page, then use   instead.