Thanks in advance for any advice...
I plan on building a deck that will eventually be turned into an an game room with a 1/2 bath setup...
What do you folks suggest I use for posts and joists?
Also is it OK to use a concrete pier setup instead of placing the posts in the ground or is this a bad idea?
$$'s are abit tight but I have a few bucks saved up in the cookiejar.. what kind of material costs am I looking at?

Thanks again for any suggestions
TommyP:)

Not a direct answer, but a bit to consider:

Much of what you ask here will be determined by local codes.

For major stuff like this, I like to get a contractor out for an "estimate" then grill him with questions... like the ones you have.

To accurately answer your questions means either asking someone very knowledgeable about your local codes, or wading through them yourself. They're usually online, but they're a real bear to go through to find answers.

I think you'll find that piers are acceptable for a deck, but not for an add-on room.

I agree w/ rickj, check your local codes.
You can use that type of deck system for an addition. Built may that way where there was no way to get a machine to dig a foundation. Placing the pier on the ground is not good especially if you live in a frost prone area. Also 6x6 post, which you should use, will not fit into the pier "pocket". They are made for 4x4 posts.
How high off the ground is this addition & what are the demensions?
We used 6x6 posts anchored on 12" concrete filled sono tubes at a depth of 4' (frost level) properly spaced under the beam (3- built up 2x12's). I'd use 2x10's for the floor joists for more stability and also more insulation depth.
If you cantilever the floor system over the beam. The ratio is 4 to 1. That's for every 1' canted over the beam you need 4' back of the beam.
As for cost, price the materials out at your local home center or get on their web sites. They all have material prices listed.