Pug, I did my sums earlier this year as I was costing parking at BNE for 2 weeks, it worked out to be about $240 plus running costs from the Sunshine Coast (100k each way). I actually finished up getting a limo to take us to BNE and meet us as we returned. Cost $260 and I didn't have to drive and had a beer instead.
Think about it next time.
VT