Jeff part of it would come down to how patient you're willing to be. Selag. will take off once it gets going -- unless you have one of the clumping forms. You might check your local Lowes or HD. Every so often they get pots of Sel in for about $10 (8" pot). If you want to experiment a bit, you can contact me and I'll sell some cuttings/clumps as mine could use a trim. (The postage would likely be more than the cost of the plants) Might even have another plant or two that would interest you -- including a mini philodendron

Let's see, I've also heard of folks using Java moss, though I've never tried it. Many petstores carry it from what I hear.

How moist of a terr are you doing?

I found 1 square foot of moss at http://lllreptile.com/store/catalog/reptile-supplies/bedding/moss-coco-and-other-substrates/-/live-terrarium-moss/ for $9.99.

I've used this variety before. What are your thoughts?

I think i'll mix it in with some Selaginella.

I've never used it before ...wonder what type it is?

I'd say give it a shot if you feel the "price is right" (I've never actually purchased moss before)

If you get it, I'd recommend breaking the large piece into several smaller ones and distributing them about the tank. Do keep in mind that it may take a while to get going. The Selag will have no prob with the moss, but eventually, you may have to prune back the Selag for the mosses sake (Selag will take over, IME, if given free rein)

Let us know how it works out!
:)