Are you joking? The answer is in the email you got.... Register a new account, enter the promo code and use the $30 for clicks... Am I missing the point here?
But do I have to keep an account with Adwords? and I thought you could not use adwords and adsence at the same time?
Of course you can use both at same time Maybe you mean using Adwords to bring people to a site thats MFA ( made for adsense?) The very fact that Google themselves sent you this Go for it! You dont need to sign up to anything...