it always amazes me how everyone says the ferry is so expensive, but when you compare it to what Fraser, Cape York and Moreton Island ferry's cost to go on, it's not that bad IMHO considering it's such a long trip across the Strait. It's costing me $1310 to do my trip over to Tassie and back, not cheap i know, but take the time periods of the below ferries into consideration and it's probably better value for money cost wise to go to Tassie.
Car and Trailer prices below....
Fraser Island $170 for a 10 minute trip across the water
Cape York $145 for a crossing i could just about throw a rock from one side of the river to the other
Moreton Island...anywhere from $425 - $490 depending on period you wish to travel for a 2 hr trip