Came across this post on DS for the movies part of Sky's Now TV for an offer of £15 for 6 months. Bills at £2.50 a month for 6 months, then goes to full price. You can cancel at any time.
http://forums.digitalspy.co.uk/showthread.php?t=1830568
I thought it was a reasonable deal to give the service a try. Web site says full price after 6 months is £8.99, but email confirmation says £15.

I doubt that will be an issue for me, as I don't expect to keep it after the trial period.