BT normally waive it if you sign up for a 12 month contract. Others may have more info on this
BT
will waive the fee for Caller Display if you opt for what they call '
BT Privacy' where your number will be registered with the TPS (Telephone Preference Service - for what limited good it does)
and you make
2 calls/month or 6 calls/quarter (depending on your billing choice, though of course quarterly billing adds some 18 to 20 quid to the annual bill, I believe). The calls need to be potentially 'chargeable' (ie not to 0800 destinations) but can be to 0870 (including those at off-peak times when a calls package might make them 'free').
Other companies may charge more for it. The regular pricing from Openreach may be around the 2 or 2.50 mark and thus PN price is a discount rate compared with 'standard'... though of course line rental, 'included' calls and so on may affect the overall cost from each different telecom service and the cost of Caller Display is just something a user may need to factor in if they want to use it. (Of course, even if you don't accept calls, you might want to be able to receive SMS via landline, and need Caller Display service for that.)
To be honest, PN's pricing is pretty good for Caller Display and if the line rental was lower I'd consider them.