Not sure if this really qualifies as a deal but worth knowing about:
It is now possible to get Caller Display from BT for free if you signup for their free Privacy at Home Service.
BT Privacy at Home gives you more control over who you speak to and we provide it at no extra cost all you need to do is sign up.
BT Privacy at Home registers you for the Telephone Preference Service which helps stop unwanted sales calls.
It also includes Caller Display, which lets you see the number of the person who's calling, so you can decide whether or not you want to take the call.
Click the following link for more information:
BT Privacy at Home:http://www.productsandservices.bt.com/consumerProducts/displayProduct.do?productId=CON-3399&s_cid=con_FURL_privacy
0800 121 8000
Direct number to customer services (to add caller TPS and Caller Display) -
If your account number begins with GB - 01793591155
Any other 2 letters is 01142023650