When I read prices of 300-500T€ here in the forum, we are also building cheaply with 280T€ for a KFW 70 city villa with 125m² living space including land at 47T€.
Not included in our price is a kitchen, as hopefully the old one will last a few more years, nor a ventilation system. Since, thanks to a construction expert, we planned the incidental construction costs a bit more generously, there might also be some left over for the later planned garage and carport.
Here are a few examples:
Topic Fireplace
For understanding: We are building a small city villa, so an attic use does not seem to be planned at first.
If you want to have a fireplace, you need a chimney for it.
So that the chimney can be cleaned and also accepted, you first have to get up there.
This means
1. you need a pull-down attic ladder -> extra charge
2. you need a walkable attic -> extra charge
3. you need a roof window -> extra charge
4. you need a few stepping steps -> extra charge
5. if the roof pitch is unfavorable, the chimney has to be accordingly high and the chimney sweep needs an attached ladder -> extra charge
6. The fireplace also needs air. In tight houses this means best an external air supply to the fireplace -> extra charge.
After the whole extra charge list, we crossed off the fireplace topic and only signed for point 1 and point 2.
Shower
A nice example of something that was not included in any of the compared construction service descriptions in our case is a shower enclosure.
Only the shower tray was included each time.
Sample selection
While we stayed relatively standard during the actual house sampling (color, roof tiles, front door, windows, window sills), I personally found the sampling in the tile specialist store and sanitary wholesaler most tempting. For electrical work, there will also be a large additional item (more light switches, sockets, network, satellite system, etc.).
Here still a snow guard above the entrance, there an antenna passage stone for the satellite system, some security for windows and front door, electric shutters... well, for the terrace door it would be nice already ... etc.