Lovefilm has a wider selection of films and tv shows than Netflix. Lovefilm also offer dvds by post for slightly more. Both offer a free month trial [you can cancel easily after the free bit].
My brother uses a cashback site called Quidco. They recently gave him money for using his free trial so he ended up making money
Theres also Blinkbox, I've watched a couple of films on that. You simply pay per film.