Java Moss!
Java moss, in my experience, will grow regardless of lighting. Mine has never been picky. At one point, I had a thick carpet in a maternity tank with only an incadescent bulb in the hood. It grew terrific for at least 6 months that way.
I've noticed that at certain times there's this huge spike in the price. I have no idea why that is. I recommend just surfing the net, finding a cheap supplier and ordering some.
I, too, recommend attaching it to something. Yes, it will attach to plastic. In fact, I've had it "remove" the paint from some plastic ornaments before--no idea how or why that happened, but only the java moss could have done it.
It's imperitive to maintain the moss by pruning also. I've had it completely overrun a tank before and that's not pretty. DO NOT put any pieces or parts of it down the drain or toilet. I know this sounds stupid, but my grandmother had to dig up out entire back yard once because she got a little lax with throwing hers in the trash bin! It will grow almost anywhere.
Hope this helps. I've killed many, many aquarium plants over the years. Just never java Moss.
kev