Roof windows - What costs?

Hello, does anyone know approximately how much it costs to cut in a simple roof window in a plain gable roof? The roof is still bare and will be newly insulated. So the opportunity is good. But how much do I roughly have to invest? Just a rough idea would be great to see if it would even be an option. Anyone got an idea?

850 plus tax. Velux fully installed.

Ahh, thanks. Great. So a thousand gross is a good guideline?

It always depends on the size and the effort (Wechsel?).

Well, so far there is nothing at all. So first a hole has to be made. Are there more than 1000 after all? I don't know the size yet. Something standard?

Also consider the following effort. The vapor barrier/vapor retarder must be properly connected, cladding (drywall or similar) is labor-intensive...