Just bought a cheap Xbox One from Ebay... Logged in today and usually you get the option to add Xbox live for £5.99 a month but came up as £1.
Someone reported that this was appearing on the dashboard last month but didn't seem to work for me at the time.
02/11/2016 Xbox Live Gold Completed £1.00
01/11/2016 Screamride for Xbox One (Blu-ray Edition) Completed £5.99
29/10/2016 Dead Rising 3: Apocalypse Edition Completed $10.40
25/10/2016 State of Decay: Year-One Survival Edition Completed £6.60