A raffle is just like a lottery. However, instead of buying lottery tickets, you buy raffle slots. A raffle will tell you the max number of slots it has. You can buy as many slots as you want. Once all the slots are filled, a winner will be randomly drawn using random.org. If you are the winner, the host of the raffle will contact you to give you your prize! To calculate your chances of winning, use this formula:

chances of winning = [(#of slots you entered) / (max slots in raffle)] * 100%

For example, if you entered 10 slots, and there is a max slot of 50 in the raffle, your chances of winning is:

(10/50) * 100% = 20%