Did Yahoo really send me a email today about winning a prize?

I recieved a email today called Yon Won $500!Yahoo Congratulates you! Is this a hoax? should I trust this.It claims it is from yahoowinners@yahoo.com.Claiming it gives out random cash prizes and yahoo congratulates me.Then it goes on to say it needs to be sent to Pay pal or some other website acct.It also goes on to say in order to get it I need to sign up for yahoo games.(That is not a problem if it is real!)I just wanted to know if this is for real.I did not want to go any further until I found out if this is real or not.Please let me know thank you. Fran