How much house can I get for my budget?

The Musketeer already wrote that to you above.

What is the OP supposed to do with the already existing plot of land if he buys a property with existing buildings?

If it exists, it doesn't eat any bread

He can use it as equity, sell it, or build on it later. The statement "he already has a plot of land" – although we don't know where he got the land from: paid in cash, inherited ...? – does not obligate him to recklessly fall into debt.

Rhenish greetings

Basically, I would manage nicely with 300k for the house, garage, etc.? Then I quickly save an additional 100k as equity for the land.

Then I quickly save another 100k as equity for the property.

Well, I don’t know what the others think about this ... but when I read something like that, I have little desire to waste my limited free time on your questions

Regards from the Rhineland

Phew, that will be difficult with the amount if you can't add more funds.

You can take a look at the Stadt&Land people on their homepage, there you also get prices displayed - just to get a simple overview. It should be noted, however, that these prices are without a basement and only with the most basic equipment. But maybe that will give you a feel for the prices.

Otherwise, if you want to do a lot yourself, there are companies in the prefabricated house center that mainly specialize in shell houses.

I am also firmly convinced that with infinite time and the appropriate rules of technology, one can build the entire house oneself.