The following was provided by a third party. I provide it without comment or endorsement. Read it as you will:
Freelotto.com is a shady, yet legitimate company. It makes most of it's money selling your e-mail address to other companies and advertising through SPAM e-mails. While they will give some money out, your e-mail will be flooded with SPAM and other commercial e-mails.
Also, many players have accused the site of pressing them to buy merchandise or pay membership fees in order to collect prizes but never delivering the prizes they were told they won.
In addition, the prizes are often in the neighborhood of a dollar. While the company is taking your registration information and selling it to other marketers.
My advice would be to ignore the email.