Sliding glass door prices. You may purchase a sliding glass door for $400 to $700. This will buy you the standard 5 foot to 6 foot sliding glass door. It will be made of an aluminum frame and glass windows. An 8 foot door of similar construction will cost $950 to $1,200. A nine foot door will cost $1,000 to $1,200. There are even 12’ sliding glass doors on the market with a cost of $1,500 to $3,000 for a door with construction of aluminum and glass. There will naturally be more panels on this size door; 4 or more. It will cost $400 to $1,200 to hire a company to install your glass door.