Emile Woolf are cheaper IF you download the electronic version to a tablet or reader (about £10 if I remember correctly) – BUT – these cannot be printed.
If you purchase a hard copy version they are on a par with the usual suppliers and are about £40 I think.
Personally, I only bought a couple of electronic versions mainly for revision practice but didnt really like them, but only because I like to be able to scribble notes on pages.
I have heard off many other students on here that they are just as good as the other suppliers.