I was all over the depot today I knew they had white finished board the guy was puzzled very special people work at my local depot. That was my original idea for the walls

they got this 4x8 particle board that has silver insulation on one side. its Under $10 a sheet

Youll make it work bro, just take a huge bonger and wander the isles of h. depot. What looks good for you is what you should go with. I painted my bare concrete floor with garage concrete paint. Works well and cleans up easy, only issue is where the table leg is it rubs off a bit with the weight.
I like water/humidity resistant material. I have learned over the years of construction, not just a grow room but many projects. O yeah metal studs arent much more than wood, but you do buy the stud and the track, track is the horiz, stud is the vert. Screw em together with self tappers.
good luck
hiboy

Thanks guys also love the dazed walks around hd. Then trying to talk to the very gifted workers also makes for a good start to the day

So new room is almost finished final size came to be 12ft x just under 8 ft. Hopefully have it wrapped up by this weekend and start cracking some beans. Ill try and get some pics up soon.