[Aussie Mike]

I have about 450 sq meters of driveway and I paid about $36K. I went with exposed aggregate concrete as a big expanse of plain concrete looks pretty ugly in my opinion.

You also need to think about what will be driving over it. Around our area a lot of people by the big blocks as they own trucks. I went with F72 mesh and 5" thick everywhere for resale value of the property if we ever move.

You should also look at drainage as an area that size can collect a lot of water. I got a bunch of storm water drains put in and have no problems with standing water.

Cheers