Carport/Pergola Design?

Hi, has anyone done a cost evaluation of a carport/pergola using both treated pine V's steel? I actually want to construct a simple gable roof freestanding entertainment enclosure and have been looking at using a kit carport for around $3,000. I'm happy to use treated timber as a more aesthetic look but do want to use colourbond roofing and guttering but unless i purchase a pre fab kit i'm also unsure of how to design it if using either steel purlins or timber so i'd also like to know if anyone has any links or plans to make the project? Size is to be 4.3m x 7m, 6 posts,gable, 10-12 deg pitch roof, custom orb corrugated colourbond roofing etc....

I did mine in steel but I did not compare prices to timber, I just did not want a 300 x 75 timber ridge beam when I could use a 150 x 50 RHS.

If I were you, I would get a couple of quotes in both timber and steel and decide from there.

Alan