Popped into Tesco's (Brighton) Yesterday & noticed the basic Fantastic Beasts Panini sticker albums were free. You can find them in the magazine section usually. Be sure to pick one that has the barcode stamped out with "FREE". If you don't see any of the albums or packs, maybe ask at the customer service desk.
I'd already bought the starter pack at £2.99 & have completed my album. But thought someone might find this useful.
It's a quite a nice album which is also reversible. With one side Fantastic Beasts & the other Harry Potter.
I completed my album for approximately £38-ish including the starter pack & a few extras I had to get on eBay.
Not sure if its Nationwide, but I've heard it is.
Sticker packs are 50 pence or a box of 50 packs is £25. You can also order up to 40 stickers directly from Panini for 14 pence each with £1 shipping. Quick shipping & they take PayPal.