If you're looking for budget accommodation with a difference try the Jailhouse in Christchurch. It is what it sounds like, a prison built in 1876 but converted to a hostel in 2006. Your room is actually one of the cells but the hostel is very well equipped with everything you'd expect and the prices are very reasonable. It's also within easy walking distance of the city centre so a great base to do some exploring from.

My wife and I stayed there to celebrate our 25th wedding anniversary, she made the booking it so I'm not sure if there was some sort of subliminal message in that.....

Google 'jailhouse accommodation christchurch"