I have found moss, to be ok to place around the eggs, just if the moisture is low. But for a substrate, I would recommend a 50-50 vermiculite and perlite mix. Worked good for me in the past. Moss must be top grade from the best source. IMHO not even worth the hassle, unless it is for high humidity (tropical) snake eggs.
Worst comes to worst, use perlite. It is not bad, I just find vermiculite better and a mix even better than that.
Vermiculite is avialable every where you look on the net (very cheap stuff), any garden store or THE HOME DEPOT. It should not be hard to find at all! Make a few calls!