I understand that cost is an issue so my post will not be much help, sorry, but I thought it worth typing any way.
I've been to Munich, Brussels and Madrid on stag do's, three nights for around the £150 mark.
Top jollies all of em, have also been to Butlins in Minehead! that was OK. Notts was ok, but abroad just seems more fun.
Am off to Hamburg next month for another gentlemans trip.
Never done Blackpool so cant comment, sorry.