deck doors install ?

What will I be looking at as far as a price to get the french doors installed going out to the deck? I need the hole cut out also to put them in, right now there is a window in the spot.

I went to lowes and home depot and no luck, they will both install a door but will not cut the hole for it. They tell me it has something to do with the header, makes no sence to me. If you install doors for a living, you should know how to install a header, correct?
How come I have a feeling I'm going to pay an arm and leg for these job.

 

Depending upon the load (one-story, two-story or more), the size of the rough opening required for the French door(s) that you choose, the type of siding (brick or vinyl, etc.) that you have, and any moving of electrical or plumbing, it can get to be a major ("expensive") turn-key job.
The carpenter or contractor may have to build a temporary frame wall to support the load between the room floor and ceiling set back from the opening, and hang plastic to prevent dust from getting into the rest of the house. An electrician or plumber may need to be called to re-route wiring or pipes. And then the rough opening header and framing will need to be installed before the door installation.
Once the door is installed, it will need to be trimmed out, and the trim, and possibly the interior of the door itself, will need to be painted or stained.
You can get quotes for the specific work once you select the door, and get the requirements.
Good Luck!