You should try expanding your search for Cypress Mulch. Most home improvement stores have the stuff seasonally (you may have to wait a couple of months). I currently use a mixture (about 50/50) cypress mulch and coarse aspen bedding. The aspen helps keep the cypress dust down so a burrowing animal won't get it caked in its mouth/pits.
For snakes that don't burrow very much I just use straight cypress mulch. However, I take all of the big and/or sharp peices out of it and pour boiling water over it in a HUGE rubbermaid container (that's a little extreme, but I'm pretty anal about my animals' conditions).
If you can't find cypress mulch right away, you can use aspen. It doesn't hold humidity as well as cypress and you have to make sure that you don't get a dusty variant of the stuff. You generally get what you pay for with aspen. The cheaper stuff is pretty dusty!
Tom