Toilet from €27.90 to €500 - objective information on the price difference?

I have just read the three pages of this thread with great interest and unfortunately feel confirmed.

We are working with an architect and awarding the trades separately. The first offers from the electrical and sanitary sectors have started to come in, which caused me slight shortness of breath.
Offering a Gira flush-mounted radio as a provisional item with more than a 100% markup is really borderline. I might perhaps accept 20%.
In the sanitary sector, they have directly skipped itemizing individual positions and instead offered only the complete shower. Maybe so that I can’t figure out what the 90x90 shower tray is supposed to cost me?

At the moment you’re running. If they don’t have two left hands, they have more than enough to do. And most take what the plumber presents to them in the "exhibition," or an upgrade.

In the sanitary sector, they skipped listing individual items and preferred to offer only the complete shower. Is it so that I can’t understand what the 90x90 shower tray is supposed to cost me?

Why do you care about the price of the tray if you want a whole shower with a warranty? Either the price for the shower is right, or it isn’t...

Sockets and push buttons are still pending for me... I'm very curious about what will be called up. Maybe it will work there like with the toilet flush: I'll buy and install the push plate myself.

Well; with sockets it mainly depends on the number of available sockets; or gimmicks like multimedia/network and similar features or even just plain empty conduits.

Only in second place are there surcharges for better switch designs.

We build turnkey with GÜ. When we were then shown what was so great about it, we looked at the sample chooser and said in unison, "Paint it." As long as the 3-level sales system is still alive, the customer will always be the sucker. You pay endless amounts of money for something better, but the credit is more than meager. Still, we are at about 5k for the material for 2 bathrooms. And except for the bathtub, I actually don't see a big problem. A washbasin is screws; anyone who keeps their strength in check will manage it. A toilet is a bit fiddly at first, but also not a big issue. Regarding electrical: in my opinion, the surcharges are rather moderate. Ultimately, more sockets also mean more work for the electrician. However, if you want certain "special frills," you should carefully consider whether you really need them.