The one thing to be aware of with WordPress Amazon affiliate plugins is that you don’t want to use one that offers link cloaking. This is a method used to protect affiliates from a threat known as affiliate link hijacking. However, Amazon expressly forbids the cloaking of their links, so you’ll want to avoid plugins that do that or always be sure to disable that functionality if they give you the option.
The phrase, "Affiliates are an extended sales force for your business", which is often used to explain affiliate marketing, is not completely accurate. The primary difference between the two is that affiliate marketers provide little if any influence on a possible prospect in the conversion process once that prospect is directed to the advertiser's website. The sales team of the advertiser, however, does have the control and influence up to the point where the prospect either a) signs the contract, or b) completes the purchase.
You can sell your ebooks through Amazon's Kindle program or Apple's iTunes Connect, which gives you access to a large majority of the digital-book reading market and the barriers for entry are incredibly low. You don't need to invest lots of money to make this happen, but you do need to invest lots of time, not only in writing the ebooks, but in marketing them as well.
You may have noticed in my overview of the Amazon Associates site that I left out the mention of the plugin they built for WordPress. That’s because the plugin doesn’t work (at least not well). Luckily, the Amazon Auto Links plugin will simplify the process of finding new and relevant products to promote and creating affiliate links to them--all from within WordPress.
There are many ways to get people onto your list. Lead magnets are one such resource. For example, you can build ebooks, checklists and cheat sheets. But you can also do content upgrades, such as PDF versions of an article with added resources in them, four-part video training series, and more. Think about your audience and what you can offer them to better serve them, then treat them with some respect and you'll eventually reap the rewards.
I have a free WordPress website with 1000-2000 visitors/month. I was trying to place Amazon Affiliate ad links last night and failed/flailed mightily. I would paste the links into my posts in the HTML mode, switch to Visual mode, and could see the image. However, every time I tried to save or update the post, the image reverted to the gangly hyperlink. As some suggested, I tried cleaning the links of any formatting from the copy and paste with text edit. No dice.