Add Affiliate Banner to post

Good evening,

I’m new to www.remarpro.com, so please have some patience. I’m trying to insert an affiliate banner into the bottom of a post. I’ve managed to add an affiliate link to a sidebar widget, but I would like to add one to specific posts. I’ve figured out how to add a simple text link, but I specifically want the banner.

When I’m creating the post, if I go to “text” and add the html code there, it doesn’t work. My site is allthesefeathers.com. Here is the code i’m looking to add:
<iframe src=”https://rcm-na.amazon-adsystem.com/e/cm?t=allthefea-20&o=1&p=13&l=ez&f=ifr&f=ifr&linkID=C6CG65NAYID3FAQI&#8221; width=”468″ height=”60″ scrolling=”no” marginwidth=”0″ marginheight=”0″ border=”0″ frameborder=”0″ style=”border:none;”></iframe>

I’ve tried a couple of syntax plug ins, but I just end up with a box with code in it. Any help would be greatly appreciated.