OK, just for PW members, I want to share an affiliate program to which I belong.
It's a company called Bookcloseouts. They sell remaindered books--new books publishers have sold off at lower than their usual price--and some "scratch and dents"--books returned by bookstores with minor blemishes.
They pay a 13% commission, and have a long cookie (as far as I can tell). And they allow you to buy through their own links. You can link to individual books, sections of their site, or special promotions (they usually have a new promotion every month). You can also set up a search box.
They are based on the US/CA border so will only be good for you if you have visitors from those areas.
I have not made huge amounts from them but that's partly because I hadn't been featuring them, I think. Now with AdSense sliding, I am now trying to make them more prominent. Here is a sample, up on my What's New page: