Keeping things short.
SCAM message can be in form of sms, email, letter, or calls.

SCAMMERS will contact you and tell you a LONG SUCCESS STORY to capture your attention. And at the end of the message you are asked to pay a token (like #2000) to get your reward (like #2,000,000,000). Don't do it.
Some might say the more times you try the higher your chance of getting/winning the reward (#2,000,000,000).
So when next you see a long success story and at the end you are asked to pay a token... well it might be a SCAM. You'll see this kinda of stuff online alot

Another common method is to send you a message or call you to congratulate you for wining #2,000,000,000 that you know you didn't work for or apply for. And then they ask you to pay for cost of transaction of sending you the cash. It most definitely is a SCAM. A lot of nigerian gsm service providers use this method.

Money doesn't just fall into your lap. beware of SCAMMERS.

When you notice a new SCAMMER spread the news to your friends (and enemies if you don't hate them enough).