We don't use humid hides for any of our bloods/stps, but do utilize long fiber sphagnum moss for nest boxes. Just search for it online - you can usually find better pricing than you will at a hardware store type place.
Here's a good resource if you want to keep your $$ in the herp industry: http://www.joshsfrogs.com/substrate/...moss-800g.html
(I have no affiliation with that company...have ordered feeder insects in the past & they have great service.)