amazon.co.uk has a promotion called "2 for &7 on select paperbacks". When trying to use the promotion you will find out that it works only for a maximum of 2 books.
Amazon customer support says that the rule is written in the promotion and it is stated here (which clearly states that if you order 2 books and then return 1 you will loose the discount) :
The Offer is subject to a Minimum Purchase requirement of 1 time per checkout:
(i) if you remove Qualifying Items from your Basket, so that the combined purchase value of the remaining Qualifying Items at checkout falls below the Minimum Purchase requirement, the Offer will cease to apply;
Am i the only one that doesn't see an upper limit here?
and here is the link.