Buy One Get One Free
One of the largest supermarkets in the UK has tried to address the problem of waste with a new take on bogof offers.. Now it's buy one get one free 'later'..
They plan to issue customers who buy one of the offer items, a voucher/coupon which can be redeemed up to several weeks later for another one of the product bought.
Sounds like a good idea that the others will probably copy too... what do you think?

...how do they do that?