Your raffle are not provably fair or at least players cannot be sure they are fair .
You should state clearly how do you choose random winners.
Fo example you may associate every ticket a progressive number (known by the player issued with that ticket) and then use public sites like random.org and make a movie of the random selection and upload it somewhere on the net.
Otherwise you are only attracting players and make them wager on your site with a generic promise of a random prize, but no one knows (except for you) how do you chose those winners.
You realize like none of there games are provably fair, not just the raffle, right?