Yesterday while checking about Amazon Affiliate and another affiliate program that I won´t mention. I found out that even if you do not or cannot have an affiliate ID., now you can easily go the people who supply amazon and be an affiliate of theirs instead.
Of course this is only likely to function for people inside of the U.S. as people like Share A Sale and Commission Junction usually are.
Allposters is an International program also that will work well for some but with these you really ought to have your own website and make deeplinks with your own all posters affiliate id: so that you really can get paid.
This why this program insists on this.
Although you can use their Posters on other websites if you are trying to make money real money it´s always better to deep link all the links you do whether static or rotating links too.
Allposters posters are very nice to use as photos alternative on your websites but again you run the risk of not getting paid any sales for not doing the right kind of affiliate link from the start.
Just adding here that Barnes and Noble is one of those very affiliate programs. Anyway you can google and get the others as I am not an Amazon Affiliate and I am not into that. I write on Squidoo every so often and will post an Amazon Module but that is to do with them mainly.