Google Adsense

Google adsense is the most known for most of the users of course it's from google, it also means that it's trustable, you have to use it like this:
1: generate the code of the ads
2. Copy and paste them on your page,
And that's all every time a user click on one of the ads they pay you and when you get 100 USD at the end of the month they send you a check to your home that means that you have had the age to receive the check you can sign un on the next:
look at the end of the pages the type of advertisements and on the bottom you could register clicking

example 1