Adding Amazon affiliate links won’t work

Hello. I’m trying to add some Amazon affiliate links to specific products on a WordPress page. You choose the product on Amazon’s site and then copy/paste the specific code to your account.

The code begins with an <a href= tag. Seems right. When I paste that code to make a link WordPress always begins that tag with my blog’s URL before the <a href= tag so it comes up as a 404. I’m using the visual editor. I know a lot of people don’t like the visual editor but it’s sooo much easier to use if you don’t write HTML code. It works when I click over to the HTML tab and paste it in that way.

Is there an easy way to do this in the visual editor or a plug-in that makes this work? Thanks.