买300送100用英语怎么说

买300送100
You get 100 dollars cash rebate (如果是送代金券 voucher for freem) for every 300 dollors spent.
买300立减100
You get 100 dollars off for every 300 dollors spent.
满200减100
You get 100 dollars off for every 200 dollors spent.
满198送98元券
You get 98 dollars voucher for free, for every 198 dollors spent.

$100 cash rebate for $300 purchase

$100 rebate for $200 purchase

$98 coupon with $198 purchase