A word of caution.
Some time ago I set up several sites running Amazon code to display various products. After a considerable time I noticed that most sites did not even have any clicks. On contacting the support at Amazon I found that the first domain you registered with them counted, all subsequent ones did not and therefore no clicks were recorded.
They must 'approve' your domain first before they set their clickthroughs in motion. So if you set up many domains with the same Amazon code and i.d you need to alert them and get them to approve each site.
Thought you good folks would appreciate the heads up.