Cheap accommodation in Sydney for 16 nights?

I've just booked flights to Sydney for mysellf and my wife, my mother and father and my 2 sisters. We will be flying out early March 2008.

Can anyone suggest the most suitable (fairly cheap) type of accommodation for this short stay?

A friend suggested hiring a Camper van for the 2 weeks...any ideas welcome?

We stayed at Y on the Park in Sydney. Smack bang central Sydney located beside Hyde Park. Cheap Budget Hotel accomadation, we had rooms not ensuite but bathrooms beside us and very clean. We were staying with 2 kids and needed cheapest, central accomodtion. Only concern was noise from traffic, it's on corner of Oxford St. I'd then hire car and head out around Sydney...Blue Mountains, Hunter Valley. Check out Big 4 website they are Caravan Parks with huge range of accomodation from chalets, mobile homes and villas. All self catering.