Buying premade Wordpress website + amazon affiliate

Yeah, and you certainly aren't going to get rich from AdSense until that traffic is in the millions per month. I'd steer far away from this if I were you unless you already have a way of getting a tremendous volume of website traffic. This "here's a website; all you need to do is get people to come to it" scam (for lack of a more appropriate term) has been around for more than a decade.

I think it would be pretty hard for Amazon to tell if a site was a cookie cutter mass auto site. So many sites seem the same because they copy and paste the same information every other site (including Amazon) has.Of course, that's assuming you are located somewhere that Amazon allows affiliates from.

Note: I have a funny feeling Amazon will be adding back all of the states it formerly disallowed, due to the recent Supreme Court ruling on sales tax. It's either that, or they get rid of the affiliate program altogether since affiliates in every state will be subject to sales tax. Then again, they just might decrease commissions.

IF (big "if") all of the products on this site are available on Amazon (they likely are), you'd stand a far better chance making money through an affiliate program but I wouldn't count on "quit my job" kind of money.

That said, you still better know how to market the site and drive traffic to it because a pre-made site is extremely unlikely to rank well in the search engines without re-writing all of the content and then getting some decent links And, you're never going to be able to afford paid advertising with this type of affiliate website.