A good strong long term A Board should be £150-200. You'll see cheaper yes but they will either break in the mind or just cheap rubbish.
I can't make that sign picture any bigger I'm afraid so hard for me to tell but seems like brushed metal letters on stand offs to me attached directly to the wall.
Prices for these vary very much on size and how many letters. I'd say a standard sort of size is going to be between £20 ish per letter. Possibly a bit more.