Would you consider a volume discount?

批量购进可以再优惠吗?

If you buy 1000 or more, you'll get a 10% discount.

如果您能购进1000件以上我们就可以优惠10%。

Could I have a lower price?

可以给我便宜点吗?

Could you give me a discount?

能给我个折扣吗?

How about buy one and get one free?

买一送一怎么样?