Sky Broadband Unlimited free for 12 months.
£17.40 per month line rental
However, you get a £100 Prepaid Mastercard
Potential £63 Topcashback
Total cost over first year £45.80 - price displayed excludes the Topcashback.
EDIT: Cashback reduced from £72 to £63
Also need to pay £20 for connection - so £228.80