There are other programs that are useful only for promoting websites or URLs. These can in turn help you to earn money in other ways, such as making sales, or getting referrals. Many programs asked for you to pay some money in order to progress to make money for yourself although you can join for free. This is very risky, and smells of potential scam, or at least potential failure as any MLM-type scheme would turn out to be. Therefore, it is NOT recommended to pay any money, unless you can afford to lose it. Join for free by all means, but be very wary of any schemes that require payment of any amount. Even a one dollar payment can add up to millions of dollars' windfall for the organiser if many people fall for it.

New schemes are especially fishy, you can check how established they are by their Internet rankings (PR, TR, etc.), which are posted next to their banners here. They can fold anytime, as had happened to many GPT sites. As a rule, an established site has been around long enough to get a PR rating of more than just zero, and a decent Alexa traffic ranking. The website valuation and backlinks widgets give a rough idea of how established the site is. These figures take quite some time to improve, and not overnight. Check them for a while before committing yourself to an investment. Sales talk is cheap, and so-called figures, statistics, testimonies can be made up easily. Online guarranties are not reliable. So be warned!