I quite liked the small packets of Randoms (you can usually rely on Rowntree for decent confectionary), and recently they were released in larger packs.
In both the modern Co-operatives and the older style ones these large packs are only £1. Possibly Somerfield as well (can anyone confirm this?).
If you are unfortunate enough to work in a Co-op (which alas, I do) you can get an added 10% staff discount as well.
This deal is only around until the 19th I believe.