I got a cheap kitchen gram scale at my local grocery store for $10. Any scale will work, as long as it weighs in grams. And, I use sphagnum moss. I put it in a bowl, and then I get it wet. I leave around 1/2 to 1 inch of standing water in the bottom of the bowl with the moss, and that helps it to not dry out so quickly. Just make sure to change it often and you should be good to go.