You can get any number of roof coverings. You can choose from asphalt shingle, wood shingle, tile, metal, and slate. Asphalt shingle is your cheapest option. It is possible to re-roof it yourself with these shingles. Tile is a very durable material and will last longer. It will also provide better protection. It costs a bit more than shingles. Slate is your most expensive choice. This type of roof lasts the longest as well. When it comes to quality, you really do get what you pay for. Depending on locality, the cost of supplies and labor can vary drastically. Two different locales can have price differences in the tens of thousands!
In some cases, all that is necessary is to lay down another layer of shingle. But in other cases, you will need to re-roof which adds to the cost.
If you have one of these, you will need to make sure that the contractor you choose really knows what he or she is doing. Some people have experienced leaks after a new roof has been put in because the contractors did not do quality work when it comes to the area where the AC is mounted. It takes expertise and good workmanship to re-roof in the presence of a roof-mounted AC unit. This adds to your cost as well.
If any structural damage is found during the process, your roofer will recommend that you get this repaired before continuing. Many roofers are capable of performing this task as well at cost, of course.
Taking the above into consideration, you can do a preliminary visual check yourself and see if you can spot any items that may increase your costs. Of course, if you live in a HOA, your roof cost is depending on the type of roofing material is acceptable in your neighborhood.