You don't have to use the Libre all the time, each sensor should last up to 14days, ~£50 a piece (you can tick the VAT exemption box!) you can buy the reader which is also a blood glucose and ketone tester, for which your GP can prescribe the strips for (!? as many as you NEED lol) - many diabetes clinics have some readers and sensors given to them by Abbot ask yours if they have any (free!).
If you have a compatible Android phone you can use an app and the NFC of the phone to scan the sensors, saves another £50 on the reader (if you had to buy one).
Been warned there is one major issue with the Libre.............once you've used one you'll want more!