Intentional deception for gain
Do not believe everything you read. If you do not know who it is coming from and they are advertising something, most likely it is fraud. Fraud and spam go hand and hand together. Spam messages and all frauds. If it seems to good to be true, it probably is.
If you are extremely gullible and do not know what is real and what is not, then it is smart to learn how to tell if it is a fraud. There are two ways to do this. One, research the institutions; looks at costumer ratings. Second, just do not reply to the emails that seem to maybe not be true. This will limit the spam messages you receive because other spam companies will not know your email as easily.