[Pasting the code directly into the site did not work for me, so I did need to use the workaround linking to the external image and then editing the link.]
Using PayPal with Google Sites
posted Apr 23, 2009 11:45 AM by Brian Johnson [ updated Jan 27, 2010 7:59 PM by Brian Johnson ]
The code that PayPal provides for embedding buttons and forms into your website will not work with Google Sites due to how they are put together. As you know, Google Sites is fairly restrictive in the custom code it will allow, and the <FORM> tags that are necessary to make the PayPal buttons work are rejected because of this.
Despite the limitations described above, it is possible to include such things as a PayPal Donate button on the pages of your Google Site. To do this, follow these simple instructions:
PayPal
Log into your PayPal account
Select the Merchant Services tab
Click the Donate link under Create Buttons
Complete the "Create PayPal Payment Button" wizard and click Create Button
On the "You are viewing your button code" page, click the Email tab
Copy the URL from the text box to your clipboard (<CTL-C> for Windows users)
Example: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=4949195
Google Sites
Log into your Google Site
Navigate to the page on which you would like to display your Donate button
Select Insert >> Image and choose the "by URL" option. Paste in the URL for your PayPal donate image:
Click the Add Image button
Position the image how/where you would like it to display on your page
Select the image
Click the Link icon on the Edit toolbar
Paste in the link from step 6 on the PayPal instructions above
Check the Open this link in a new window box if you want a new window to open when the image is clicked
Click the OK button
Save your page.
Site:
https://sites.google.com/site/gsunhelp/step-by-step-guides/usingpaypalwithgooglesites