Some possibly useful links

http://paulmoneysavingtips.blogspot.com/2008/11/saving-money-on-dvds-similiar-items-and.html

2012-Doomsday

This is about some travellers in mexico who get drawn into the 2012 mayan prophecy the world will end in 2012.
On ebay from 50p(23 august 2010),tesco from £5
Search Amazon.com for 2012 doomsday

The fourth kind

In this film,a psychotherapist discovers evidence of alien abduction via hypnosis in an alaskan town.
Avaible on ebay from about 99p(23 august 2010),compared to tesco £7

Predator films

Predator starring arnold schwarznegger
Arnie and a team of commandos are being hunted by a predator in the colombian jungle
Amazon from 1 cent
(6 august 2010)on ebay from 50p
in tesco from £4