Is it really possible to build for 150 thousand euros?

Thank you very much for all the contributions, really very helpful. I have now obtained offers from 3 of the affordable providers here in the north (Team Massivhaus, Heinz von Heiden and Town & Country). It turned out that with all three providers the budget (including incidental construction costs, terrace, underfloor heating) is actually feasible, but otherwise really not. And I still need kitchen, carport, garden fence and many small extras. Team Massivhaus is also 8,000 euros below the other two, but I haven't found the catch there yet....

The catch usually lies in the construction service description. Heinz von Heiden, for example, does not include a portable toilet or container in the house price. Thus, as a builder, you then have additional costs. These two items and the house provider are just examples of some or a few companies.

Team massiv has built 3 houses here in the new development area. They are definitely the cheapest and the houses also look decent when finished. However, one can still imagine it as the comparison between an Opel and a BMW. We visited 2 of the 3 houses from Team massiv. You can clearly notice the difference, despite the long lists of additional costs in the mentioned houses. But that does not mean that the houses are bad.

You have to be clear, however, that the construction takes a very long time. Between signing and moving in, it can easily take 1.5 years. They are not fast.

Yvonne, read properly. I wrote:

Not easy, but it could work, but it requires more info. Your only comment was:

Nonsense or something like that.

This was about the simplest equipment. Not luxury, not high quality. Period. There is laminate for 7.95, or a whole clearance stock for 300 just as an example.
Earthworks: We just saw, that was 3 grand including connections to shafts.
Sure, if you add a pile foundation here, it will get more expensive. Therefore: read! or:

How much do 6 windows and a patio door cost? Almost a grand each if you want, plus VAT. And for another grand there’s a front door. Plus installation.

This is nothing fancy, minimum standard basically and that’s what was asked for.

If I set it up that way, I can even do it in timber frame construction, quite easily. With heat pump and controlled residential ventilation. It’s all a question of where you set the margin. Just because nowadays everyone thinks they have to get rich with a house. But those times will change again...

I gladly refer you again to #20! This also applies to the OP! P.s. And I quite boldly assume that the low-cost providers are not honest about costs that have to be borne on the construction side in the initial consultations.

Yvonne, your statement "nonsense" has not yet been substantiated. And you don't seriously want to accuse Team Unaufrichtigkeit, do you? Or that none of us can calculate? Ne dixi, those are huge amounts in the incidental construction costs that appear there. The pivotal point is the Grundstück. But those are the details that are missing.

And I said nothing else.