Camper van Christchurch to Auckland

I’ve heard the demand for campervans that are left in chch by tourists and need to be driven back up to Auckland (normally at a very discounted rate e.g $1 per day).

Has anyone used a specific company for it?How cheap was it and how long were you able to travel before needing to drop it off in Auckland?

Trying to book one but can’t find much info on it