@Melina is 100% correct that the size of your home and the type of material will largely determine the total cost for residing your property. Other things will come into consideration also: Will you be covering all of your window and door trim? Soffit and Facsia?
Siding is sold and installed by the square foot and windows/doors are generally a specific price per opening (unless very unusual or very large) and soffit/facsia are sold by the linear foot. All combined, I would think $6.00 per square foot (siding, windows, doors, soffit/facsia included) would be a reasonable quote. If it is strictly for siding, the cost of $6.00 per sq. ft. sounds very high to me.
Siding contractors are completely unregulated and you may well receive bids that are completely on opposite ends of the spectrum (very low and very high). Get several bids and get references. Cheapest is rarely going to be the best...there is an art to siding (like most other things) and you don't want the cheapest source who does a lousy job.
If you opt to put any additional vapor barriers or insulation under the siding, monitor the work to ensure that it is properly installed. Vapor barriers and insulation are costly additions to a siding job and it is fairly common for the installation of the products to be spotty, at best.
Personally, I prefer hardiplank over any over product; however, it certainly will cost you more. Now, you might wonder how a mortgage professional knows anything about siding. The truth is, in my "former life" my ex-husband and I owned a remodeling company and he was a master at installing siding. In fact, I worked with him for many years (yes, with a hammer!!! LOL!). My experience of the products and the industry are first hand, not heresay. Best of luck to you!