Manipulating random numbers

I readed really a lot forums and problems here, but cant find the right solution.

So, most of you (I hope) know freebitco.in, you can win bitcoins every 1 hour. There is the following table. If you roll a number between 0-9885 you will get the following payout and etc.. But there is a very very little chance to roll number bigger than 9885. For example the change to get number bigger than 9885 is 5%, bigger than 9985 - 1%, bigger than 9993 - 0.001%, 10k - impossible. So, how I can manipulate the rand function in php?