As you already know, there are so many variables. The main thing is, how much is your budget for the project? In other words, are you being realistic? Then take it from there.

I think the main thing is, Gus are you being compensated for your posts?

A few years ago I helped a friend build a 10x10 deck ~5' off the ground, with stairs going down to a patio slab, and railing on 3 sides. All PT lumber. Materials were around $1200. If you're hiring it done, double that to include the labor unless you're in a HCOL area, in which case you should triple or quadruple it.

We offer AZEK® PVC Deck Boards, TimberTech® Capped Deck Boards, TimberTech® Non-capped Deck Boards, and YellaWood® KDAT Deck Boards because each are the very best in their category. We're pretty sure one will be perfect for your deck!

If the budget is tight, or if you just prefer genuine wood, you can't go wrong with YellaWood® SuperSelect KDAT Deck Boards, the only grade we sell. Kiln drying after
treatment gives YellaWood® KDAT Deck Boards a huge advantage, and each
board is specifically selected for appearance and strength. It is so far
superior to regular pressure-treated lumber that it is in a category by
itself!
http://www.vintagewoodworks.com/deckcomponents.html