Thier not scams, but you have to do some research which you can do with little effort using Marcus Affiliate Market toolbar. But don't recall it this time if you have access to that information without being a member to log-in.
Also checkout the site for clarity, navigation, what is or was the offer. Is the offer still available to use. You don't want a website if you have to go find new offers for it. Go to the about us page and see you you can email the owner for more information.
Check out to see if the site is on the first or second page of google or bing. See if there's any competition Ads that might make paying for clicks to expensive. If you have been watching marcus training and webinars, he covers all these points, but just doesn't say he is. Example is when he is in Google's keyword planner.
Another thing is when you look at the site, if all you see is "Hello world" on it, don't waist your money. You can probably get the same domain name with a different extension or a modification of the domain name. And their is no reason you can't design your site after theirs, A lot of people do that. Just don't copy his word for work or you will be dinged my google and even banned from their search engines.