This is completely area driven. What neighborhood are you interested in? Zip 35801 covers the spectrum of Huntsville from older smaller unique homes, to very large custom built homes on the hillside to everything in the middle. Sorry I can't be specific but if you send the neighborhood I can certainly answer your question, I have lived in 35801 zip and have sold several homes in 35801.
Prices range from a remodel in the Bloosomwood area around $140 per sf. Five points can range from $70 to $135 per sf. Thornton Acres also is all over the map in price range. It really depends on area in 35801 and upgrades. Email me the address and I'd be happy to run comps for you.
Completely depends on condition of property. Since so much in this area is approx same age (minus new constr), the amount of work that has been done over the years - updates - can drive it way up and STILL sell quickly. If more of a fixer-upper...can be $50's to $60's or even less. Can email you what's out there if that would help.
Ruth @ Re/Max