Does CJ allow to join the network as an affiliate without any website? So if i would write them that i want to create landing pages to promote the products?
Yes you can use PPC for most advertisers - but you need to check the terms, each one is different. But, I've think you need a website to complete the CJ sign up form.
You need to submit your website url when you apply.. so I guess you need to have a website, then you make ur landing pages when accepted.
I spoke to a am from cj and he said that it is not necessary to have a website.. but they wanna have a look on a landing page you made.
Although you don't need a website to join CJ, many merchants are hesitant to accept affiliates who have no website listed. As long as you list a website that could just be a landing page for another program (or a list of the programs you promote, with links to their landing pages), you'll be much better off.
If you do have a problem joining CJ try ClickBank or PayDotCom, though I already had a site when I joined PayDotCom.