ᐅ $250,000 – Implementation of the building plan including all additional costs?

Hello Housebuilding Forum,

I hope I’m not starting this thread too early and that I’ll be taken somewhat seriously, even though I don’t have much experience with housebuilding yet.

My partner and I are planning to move out of a rental soon and get our own home. Until now, the plan was mainly to buy a relatively new house. However, I didn’t want to completely rule out the possibility of building a new one and wanted to at least get some information.

So today we visited a show home and had a very pleasant conversation with an employee of a fairly well-known prefab house manufacturer (I’m not sure if I’m allowed or should post the name here).

We shared what we were looking for in an existing house, which also reflected our basic requirements for a prefab home. I also mentioned to the employee that on property websites like immowelt or my-next-home, new construction projects with land are often offered, since we don’t have a plot ourselves.
The employee took notes on our wishes.

Between 130 and 150 sqm (1,400 and 1,615 sq ft)
Plot between 400 and 600 sqm (4,300 and 6,450 sq ft)
Basement
Underfloor heating
Painter/turnkey delivery

We didn’t express any specific wishes regarding balconies, bay windows, or similar features; it was mainly an initial conversation for information. We don’t want a townhouse but rather a fairly “normal” one-and-a-half-story house with a pitched roof.
Our total budget was stated as 250,000 euros (about $270,000). The employee said that “you can do something with that” regarding what we imagined and that he could provide a non-binding offer.

After reading around a bit here, though: is this even realistic? Can we seriously plan to get a house with a plot in this size range within that budget?

According to the employee, all costs would be covered in this offer, including property taxes, additional construction costs, and site costs.

I would really appreciate your opinions...

Best regards