Asphalt shingles are currently the most popular type of residential roof material for a variety of reasons. They are relatively inexpensive; starting at around $2.00 per square foot installed and go up from there. Things that determine cost are geographical location, slope of the roof, height of the building, ease of access to the premises, complexity of the project, the particular type of shingle and numerous other factors. They come in a variety of colors and styles, are fairly durable, and can be easily repaired and maintained.