A good portion of material choice would have to do with the "style" you are looking for. I like a surreal, dingey , almost folk-art look. It lets me use a broad range of materials. (and I can be sloppy too. Not a lot of effort to be "new and pretty" here)
Few set out to be as cheap as I am about building things. I like "free" a lot.
Much of my wood is simply scrap. Thin, vaneer thicknesses, scrap from trimming for "real" projects, or even a 2x4 sliced like cheese on the table saw (with the grain). Poles, or round timber from chopsticks, and shish-kabob skewers. Pop-sicle sticks provide planks. There's tooth picks, etc too.,. Square stock, I do buy sq. dowels at the hobby shop, as well as some "fancy" trim But some trim is homemade too.
Glass: I like clear Q-tip containers or similar
Old sheet metal from a cookie tin, a can of soup, etc. (I avoid it if heavily galvanized, it doesn't really hold paint as well). Soup cans make nice "wavy" sheet metal roofs like the old metal roofs and the metal for quonset buildings. The "wave" size differs from can to can too. On some the waves are too big.
A small block of foam will make a good base, and sidewalk as well. Light, and cheap, maybe free. Carve your cement lines, and paint.
Hardboard, or wall paneling, is an old favorite, and some has a nice texture on the backside for cement (some is too coarse). Stippling paint with a brush when tacky can add texture.(or lift the paint, but water base makes covering up mistakes easy too)
I have a Wal-Mart at the end of the block and find the .50¢ Apple barrel acrylic craft paints, suit my needs well enough, when a super smooth, or glossy surface isn't needed. Good for dry brushing, and creating washes to weather with too. Its water based, so cleanup and use is easy. Its also the best paint for foam. It doesn't react chemically, covers well on the foam. ( and seems like it lays flatter on foam than other items).
Stick with flat paints, or a semi-gloss unless you want an oily, or really shiny, toy-ish look. Check out the factory stacks below (an AF talking station bash) for shine overkill with Testor's gloss.
Black, brown, red, and/or white first, then dry brush &/or stipple grey on top to give some age to your concrete. (despite covering with grey, the base colors do change the appearance. Your eyes see more than you realize
If you want a super smooth PW, or "store bought" look, use the smooth side of hardboard, sheet plastic, and metal. And 2 thin spray paint coats dries flatter than a thick one by spray, or brush. Thinning paint, and using multiple coats by brush is effective too, but time consuming, and spray is still nicer.
Not much "new concrete", but look around pic.s for stone and old cement, metal roofs, poles etc.
You can't really do any worse .... a monkey could have done the painting better with the care I used. Spontaneous imperfections make things look better IMO.
More pictures in the attachments below, this is a "general shot".