Simple and easy to use with some cheat protection. Simply put in your figures and url so people can verify the random number.

If you try to submit another random number the system will detect that, and will give you the same number. There is security in place for a reason. You want this to be fair to the people in your draw\game.

EXAMPLES
If you do not want to enter a url, you can always use a description or even something like,
My giveaway: 'Item'