Placing affiliate ads on your wp blog sidebar is very similar to adding ads on wordpress blog post or pages except we are going to paste the HTML or JavaScript code given to you on your sidebar. You will want the ads on your sidebar a little more generic, but still dealing with your blog's content. The reason I say this is that these ads on your sidebar are going to show on every page or post, not just certain ones. So when placing ads on your sidebar, just keep in mind that these ads will show up everytime your sidebar is shown, which most themes your sidebar shows no matter what you are looking at. Anyways, onto the directions to place affiliate links or ads on your sidebar.
Go to your affiliate program of the ad you want to use on your wp sidebar.
Copy the affiliate HTML code they provide you with.
Login to your WordPress blog by going to http://domain.com/wp-admin/
Click on Design at the top left of the wp admin area
Click Widgets in the submenu section of the wp admin bar, on the right hand side select which sidebar you want to edit (if you have more than 1 and click Go or Show).
Add the widgets you want to use if they are not already there by clicking Add next to each one, place them in the order you want them.
Now that you have those widgets added we need to add a Text widget to place our affiliate HTML ad code in.
Drag this Text widget to where you want it to appear.
Click Edit on the Text widget, this will open up 2 boxes you can type in, on the top box this is for a title, we will leave it blank.
Right click on the bottom large box and go to Paste, if this did not allow you to right click, then hold Control button on your keyboard and tap V one time, this it the keyboard shortcut for Paste.
In the bottom left side click on Change, this window should close
Click on Save Changes at the bottom of your widgets.
Now View your blog and you will see your ad on your WordPress sidebar.