So I decided to base my Space Marines army with City of Death type bottoms and had recently been inspired by some other artists to try using cheap household things to model with. (One guy used only coffee cups in some pretty ingenious ways! Check youtube for a video)
I started by cutting my guys off the bases I had glued them on. (So that's why they are silver looking with Black footprints... from when I spray painted them.)
Here are some images of the bases without paint:

Items I used:
- a cut up matchbox
- a wooden chopstick
- scotch tape pushed together to look like bent metal
- cut Styrofoam
- Elmers glue
- superglue
- plastic tubing
- wire
- some screen door material i bought at the hardware store
- bits from a 40k sprue
- some round metal beads
Then I primed it all...

And finally I painted them!

I used a way bigger variety of paints than you would actually need to use. I was just toying around with different colors and seeing what I preferred.
Paints I used:
- Chaos Black (around the edge of the bases)
- Red Gore (for the wire)
- Boltgun Metal (for the base color of the metal)
- Mithril Silver (for the highlights on the metal)
- Codex Gray (for the Stone rubble)
- Scorched Brown (for the cracks between and in the rubble)
- Skull White (for the highlights on the rubble)
I also used washes at various stages. I used Devlan Mud (for the dirty/rusty look on the metal and in the cracks of the rubble) and Badab Black (for pretty much all the cracks)
So then I glues the models back onto the bases (note that I am not finished painting the models..)

There are certainly a lot of things I learned and I discovered some things I will do differently in the future. (Use Elmers glue, not superglue for chopsticks and cardboard. Mixing paint with Elmers glue doesn't give the greatest water effect, but it has potential... so I'll be playing with that more. etc.)
I hope that helps someone out there. Let me know if you have any questions and thanks for taking a look at my stuff! :)