Has anyone used sound proofing on walls in their house?

I've just spent a fortune gutting the main bedroom in our new house and I can hear the old chap next door snoring! (or masturbating )

Don't really want to pull a new wall back down! is there anything I can stick on it and re-skim over!?

Needs to be thin as i've also just had a very expensive radiator plumbed in front of said wall

cost not an option, I need sleep!