We have just signed up to BT sport and we have managed to get it for free.
To get it free we had to sign up to a 1 year deal, this deal will be repeated as long as we have the following.
BT supplied broadband or fibre optic broadband. (Our broadband is only 6meg so no chance of seeing it online)
SKY HD satellite package.( or Bt TV box)
As long as you broadband is via BT, you can get it for free, otherwise I think it was £15 a year
Chris