Sorry if this has already been posted, but I've only just found it out this morning. If you've got Amazon prime and you order something (for Christmas for example).. if you click on delivery details and select the "No rush" option, your account gets credited with £1 for a digital video.. handy for renting something for the kids over Christmas. Just with this mornings purchases I've made enough to buy a new film :)
Some might says there's no point in having prime if you don't use the delivery, but the no rush option is still 3-5 working days, which is well before Christmas :)
Hope this helps somebody out.