you could stay at Tidal River and pay nearly $30 per night for an unpowered site
This fee covers 6 people

thats great is there are six of you but horribly expensive if you are travelling solo or with your partner

A great alternative is Shallow Inlet Camping Area (not to be confused with Shallow Inlet Caravan Park next door) turnoff just before the Promontory entry gate at Yanakie.

Great place, shady sites, sheltered, pleasant camp hosts, spotless longdrops, water available, unpowered sites only, TV reception and 3G mobile reception

From memory about $10-12 per night per person and do day trips to Tidal River (about 20 minutes away)

Until Parks Victoria change their policy of charging me, as a solo traveler, the same price as the 6 people on the next site I will not go back to these areas