Timber decking prices

Hi All,

I've committed to building some decking (20 square metres in fact - what was I thinking??!) around our new house extension and would like to get some idea on pricing for the various timbers I'm considering. A recycled timber place here in Melbourne has quoted:
Jarrah: $58 sq m
Cypress Pine: $46 sq m
Blackbutt: $53 sq m.

I don't mind using recycled stuff, as I keep explaining to her indoors "it's not going to look new forever!" but I'm not sure what a good price is. Any advice or suggestions would be most appreciated.