PayPal, Google, and other sites often provide HTML code that you can use to insert links into your website. You can insert this type of HTML code, including forms, either inside an Article or using a Custom HTML Module. However, the TinyMCE editor will normally strip out this type of HTML code. So if you try to paste in some types of HTML code using this editor, it will not work, since the editor will remove the code when you save the Article or Module.

To avoid this problem, do these steps:

1. Go to the User Manager and change the User Editor to "No editor".
2. Go to the article or Custom HTML module and paste in the desired HTML code.
3. Go back to the User Manager and change the User Editor back to TinyMCE (or your normal editor).

Note that you will need to repeat this any time you want to edit the code (unless you use the alternate solution below).

Alternatively, do these steps:

1. Install the JCE editor from here: http://extensions.joomla.org/component/option,com_mtree/task,viewlink/link_id,88/Itemid,35/
2. Change the default editor (Global Configuration > Site > Default WYSIWYG Editor) to JCE from Tiny. You may also need to change the default editor for certain users, but likely not with Joomla 1.5.
3. Go to the article or Custom HTML module and hit the "show/hide" button, which should change the box to allow you to input HTML code instead of WYSIWYG text.
4. Paste the desired HTML code.
5. From my experience when you navigate back to the article or module in the back end it will already be set to HTML input, meaning the code will not get garbled. This is a bit easier than having to change the user settings each time you want to edit the code while you are testing different button settings.

Also, the PayPal code includes an e-mail address for your site. Joomla! has a Plugin called "Content - Email Cloaking" that attempts to disguise e-mails in Articles. If you wish to paste the PayPal code directly inside an Article, you may need to disable this Plugin. Navigate to Extensions / Plugins, find the Plugin "Content - Email Cloaking", and click the green check icon in the Enabled column to disable it.

It is generally preferable to create a Custom HTML module instead of just pasting the code into an article. This way you can put the link in a module position on as many page as you like. You can also put the module inside an article using the command.

Plugins are not processed in modules, so should you use a custom html module, you will still be able to have email cloaking enabled.