The 3kg Adult is £10 in Tesco, £11 in Sainsbury's
The 800g bags are on offer in both as well. The senior (the one I got for Alice) is only on offer in Sainsbury's.
£3.00 in Tesco - but they only have the adult
£3.50 in Sainsbury's but they have senior, sensitive etc in the offer.
Sainsbury's also have the 300g bags for £1.50 all types as well.