Everything I needed to make a terrarium was already around me, so that the only thing I had to purchase from a store was activated charcoal, making it a very cheap project.
So this is how you do it:
I gathered some small rocks from near a creek, enough to cover the bottom of my glass container. I was actually advised to use small pebbles like in an aquarium, but I wanted it to be a more natural look, so I went with real rocks.
Then I covered the rocks with the activated charcoal. I bought this at Walmart, a very large tub of it for under $7.
I covered the charcoal with regular potting soil.
Then I layed my moss on top. In the above picture, the moss is a very fuzzy kind, not sure the name of it, but we spent a day in the woods at the hunting club and it was growing everywhere. All I had to do was look down. The moss just kind of unrolls itself from the forest floor and brings with it a very thin layer of dirt. By the time, I put it in my glass container it had already gotten a small brownish spot, not sure if its going to make it.
Oh, I almost forgot it took me forever to find this online, but..... If you are going to put a lid on your glass jar you need the activated charcoal. If you are not going to cover it up, you do not need it.
I made another terrarium with moss that was growing in the woods beside my house, right by a creek. I definately prefer this moss. It's greener and almost feels like shag carpet.
Grumpy really enjoyed making her own terrarium with me. We put hers in a very tiny candy jar. She got a different kind of moss too. She found hers growing on a tree.
I purchased 4 tiny mushrooms for only $3 at Zzzengirl. I also bought a gnome, but he's coming from the UK and hasnt got here yet.