Update: Amazon now requires you have made 3 sales in the last 180 days top give you access to the Amazon Product Advertising API.
In order to use an Amazon affiliate software, you will need an Access Key ID and a Secret Access Key.
Here's the SIMPLEST process to get them:
1) If you haven't done so already, please sign up sign up for the Amazon Product Advertising API. click the "Sign Up Now" button on the right side of the following page:
3) If you are not already logged in to Amazon Web Services (AWS), login. Please use the option, "I'm an existing user". Login with your EXISTING affiliate account. Do NOT create a new one.
4) Click "Continue to Security Credentials"
5) Click + Access Keys (Access Key ID and Secret Access Key)
6) Click "Create New Access Key." Amazon allows you to have up to two active access keys at a time. If the button "Create New Access Key" is inactive, please delete one of your older keys, so you can create a new one.
7) Click "Show Access Key." COPY THE ACCESS KEY ID AND SECRET ACCESS KEY AND PASTE THEM IN A TEXT FILE ON YOUR MACHINE. Save that file and remember where you have saved it. Otherwise, you will not be able to access your Secret Access Key in the future. :-)
Btw, you can TEST your API keys by using the Scratchpad Tool
Here's a video by my friend Ryan Stevenson, showing the process:
If you don't have an Amazon affiliate account, then here's an even more detailed video that starts from the very beginning:
Article ID: 144
Category: Associate Goliath Wordpress Plugin