A couple other sources of topo maps: the State Land Department, $4 each last time I was there.
Eros Data Center, on the web, $4+/- also
BLM Public Lands Informaiton Center, 222 N Central. They can custom print you a topo map with land ownership (public, state, forest, private) color coded overlay.
I like National Geographic Topo Maps on CD. $99 for an entire state, with shaded relief and a name lookup feature on the later ones.