I wanted a topo of the area we are in now, no stores in the area had one, so I ended up ordering from USGS, map was $6, shipping was $5,which will give you an idea how badly I wanted it...
If you have a university nearby, ask (or look at their website) to see if they have a map library. All the universities I've attended have a full set of USGS quads for their state and some coverage of adjacent states. They generally don't let you check maps out, but they usually have xerox machines handy (bring lots of quarters).