Spot lighting / arrangement / quantity

That depends on what kind of detector you buy. There is nothing that does not exist.

200 INCLUDING motion detector? For me, the prices mainly concern the installation/connection costs.

I still have to buy my lamps afterwards - that's why I don't necessarily want to include the motion detector itself in the calculation for now. Do I have to prepare anything in advance, or will anything be more expensive at the beginning if I want a motion detector?

I'm not a pro when it comes to this. We had 2 invoice items for the motion detector:

[*]2247 Motion detector 180° UP- 6800 switch-off capable - Upper part Comfort II no multi-lens 1.00 125.00 125.00
[*]2384 Motion detector B&J UP.-insert - 101 standard insert 6812 U 101 1.00 75.50 75.50

So in total 125 + 75.50 = 200.50 plus VAT.

Ours has a small switch installed. If I slide it all the way to the left, it is permanently off; in the middle position, the motion detector is active; and in the position all the way to the right, the light is permanently on.
So basically, like a normal light switch, it also works on/off, just additionally with the motion detector function.
But we can't do any fancy things with it like a timer, or dimmed light at night, or anything like that.