A conditional rebate is when you get money back after buying something. To get the rebate, you need to do something special, like mail in a form or a receipt of your purchase. That extra step is what makes it a conditional rebate: you have to do something extra to get the money back. It's like when you make a purchase and you get a coupon at the end of the receipt that you can use on your next purchase. That's also a conditional rebate—you have to do something extra to get the discount.