I like to get my tires from onlinetires.com Good prices and in CA, so shipping to me is cheap. Another one in Ca is tirecrawler.com
I install them myself (at a neighbors house).. If thats not an option for you, see what Discount can do for you but I can't really say if they are cheap for your area.. Around here, they are about the same price as everyone if you don't take the road hazard waranty.
As for tires...
AT tires don't do well in mud..
Mud tires don't usually do well on ice (from what I've read, no ice down here)..
For a good All terrain, I've had very good luck with the BFG AT KO tires. They worked well on dirt and rocks and surprised me even on Sand (Glamis).. on sticky mud the become slicks though.
They wore well and didn't take much to balance them.. (I was replacing them at 40-50k miles and we have a rear locker which wears them out faster)
~Mark