$174. View Costs in Your Area. Installing new interior doors is a sure-fire way to brighten your home. If the existing jambs are ruined, out of alignment or are just plain unattractive, install a pre-hung door unit, which comes attached to its jambs with the hinges already in place. These are a bit more expensive but are easier to hang.
http://www.homeadvisor.com/cost/doors-and-windows/
If the door will primarily be used from the exterior of the home, it will likely see heavy traffic and various types of weather. For this reason, exterior entry doors must be sturdy and properly insulated. This can result in higher installation costs.
http://www.improvenet.com/r/costs-and-prices/replace-front-door
Exterior or Interior Door. The first decision to make is where the door is going to be placed. Generally speaking, the cost of replacing an interior entry door is much less expensive than replacing an exterior one. Due to the function of an exterior entry door, they tend to be much heavier, which can make them more costly and difficult to install.
http://www.improvenet.com/r/costs-and-prices/replace-front-door
Steel doors are one of the most common and effective doors to install, usually as entry doors, garage doors, side doors or for privacy uses. Homeowners can expect to pay between $500 and $1,230 to install or replace a steel entry door. The cost of a steel entry door ranges between $200 and $500, depending on the thickness of the door and its style. Some styles of steel door you can choose from include:
http://www.homeadvisor.com/cost/doors-and-windows/install-a-door/
Bigger sizes and doors with sidelights will be priced at higher rates. Cost to install one interior door will be estimated as a minimum charge for same day service and normally vary from $170 to $250.
http://www.rempros.com/doors_installation_prices.html
Exterior doors installation costs. Cost to install a door can be as low as $35 or as high as $990+ and actual price will be affected by a number of factors. Doors installation cost comparison chart (prices per door installed). Interior doors installation prices.
http://www.rempros.com/doors_installation_prices.html
They key is planning. Connect with local door and window contractors to get free quotes or help plan a project. Exterior doors must be durable enough to withstand wind, rain, sun, and would-be intruders, yet pretty enough to enhance the overall look of your home.
http://www.homeadvisor.com/cost/doors-and-windows/
Additionally, sidelights and transoms can add to the price when looking at front door systems, but can be picked to enhance and completely match the style of your new front door. These upgrades can cost anywhere from an extra $600 to $3800, with all the factors and options considered.
http://www.southwestexteriors.com/how-much-front-doors-cost/
The amount of exposure to direct sunlight will affect the extent of maintenance that the doors will need. A wood entry door that is infrequently maintained will probably only last about 10 to 12 years before needing replacement. You can expect to pay anywhere from $1800 up to $5000 or $6000 for a good wood front door. Fiberglass doors go one step beyond the wood door. Now available in the marketplace, fiberglass doors give the look and beauty of wood without the maintenance and constant upkeep that wood doors require.
http://www.southwestexteriors.com/how-much-front-doors-cost/
Type of Door. The type of door will have a significant impact on the installation price. Installation costs for replacing an entry door with a standard door will be lowest. Upgrades like sliding doors or French doors will raise installation costs as they require a complete overhaul of the door frame.
http://www.improvenet.com/r/costs-and-prices/replace-front-door
cost to install a front door
The cost to install a front door is $1800 to $6000.  The cost of  install a front door is $1,800 up to $5,000 or $6,000.