A great website check is on this website, they check a lot of things like certificates, reviews and so much more, if you doubt, this one is a really good guide:

For some of them I already can tell you it is a scam because I had a bad experience with them. My personal blacklist is:

Star-clicks.com. They tell you: "In the free account you make $0,10 per day by clicking adds. You can also get referrals and then you can get more. In the update ($19,95 - down from $29,95) you earn $5,00 per day AND get html to refer on your website. In the bigger update ($59,95) $7,50 for clicks + the html. 

The thing is, when you do update they make all this disapear AND the clicks are $1,60 or $0,90 or even less and then they tell you to refer to make up the money you earn less. 

So they trick you completely and then delete all the evidence.

Clicktockptc.com. I did not spend any money there but they don't offer clicks. So it's a waist of time to even go look there. 

Bap.money Bap.life and Bap.cash. All 3 have suddenly disappeared. I know a lot of people who invested in it!