I use Oneroam, it’s 25p per minute to phone a landline number in the UK from abroad, and it costs my Missus 9p a minute to phone me and I don’t pay anything to receive the call.
The Simcard costs about £15 IIRC, and it fools your mobile phone into thinking that it is a landline in Estonia. You then have to phone through a re-router which takes a few seconds more but the savings are well worth it.
I’ll just add that this is a subject which affects anybody who drives into Europe (or goes there on holiday) and I don’t personally think this thread should have been moved to a part of the site that no-one ever visits.
From what I can understand all Mobile networks will be 36p to make a call and 18p to receive or lower after September
I am on O2 one rate 300 which gives me 300 minutes of inclusive minutes across Europe for £40 a month then 20 pence a minute after that. I’ve had it for about 8 yrs now