There have been times ( I forget) when something is given away (free) or discounted and all the buyer had to do was pay the whole tax on it. They were not usually up-front things , but corporate monkeyshines like AOL free disks and the likes.
A Rebate generally requires that the customer pay taxes that in reality they should not be liable for, and that always works like that. You pay whole, then eventually get a refund but the tax paid is never refunded.