Buying land? - The standard land value in this area is 270 euros

My uncle basically still wants to get money for it

I must have misunderstood then.

I still haven't quite understood what your plan is or what exactly the uncle's wish is.

You don't want to build there. That is a fact.

So why should you buy, inherit, be given, lease, or do anything else with the property? If he doesn't want anyone else to build there, should he keep the field, tear down the old shack, and set up an orchard? Or plant potatoes?

Why should you spend money on something you don’t need? To make the relatives happy? That is not your responsibility.

Why should you buy, inherit, be gifted, lease, or otherwise acquire the property?

Quite simple. Get it cheaply now, hold on to it, and sell it later at a profit if you want to build yourself (or, for example, after 10 years, if a speculation period must be considered to repay a loan for the new construction elsewhere). If I can get it cheaply, then I will do it. What was it about a gifted horse again? Of course, this only applies to acquiring full ownership for free or extremely cheaply.

Quite simple. Buy cheaply now, hold, and sell later at a profit if you want to build yourself (or, for example, after 10 years if a speculation period must be considered in order to repay a loan for the new construction elsewhere).
If I can get it cheaply, then I will do it. How was it with the gift horse?

Of course, this only applies to acquiring full ownership for free or extremely cheaply.

That was the original plan!

Yeah... but it could go wrong, because the uncle apparently wants to get back the purchase price from back then? That's how it sounds now? And will it really be worth more in 10 years, or exactly when you need it? Will you find a buyer exactly then? You don’t know for sure either...

There are more sensible or more diversified ways to invest your money, or even to take out a loan now...

If he wants to give away the property, then definitely take the 15 or 20% tax, no question. But if he wants to screw it up or even build a house on it, with the promise that you will inherit it someday... then... what for?

Yeah... but it can go wrong, because the uncle obviously wants to get back the purchase price from back then? Is that how it sounds now? And is it really worth more in 10 years, or exactly when you need it? Will you find a buyer exactly then? You just don’t know for sure...

There are more sensible or more widely diversified ways to invest your money or even to take out a loan now...

If he wants to give away the land, then definitely take the 15 or 20% taxes, no question. But if he wants to waste it or even build a house on it, with the promise that it will be inherited someday... then... why?

I think that already reflects character traits quite well and thus the complexity of the (social) situation. There are still some pitfalls, but going into those now would just be unnecessary detail.
He bought the land back then, basically wants money for it, but at the same time wants to have a say in the house (appearance). He absolutely wants it to stay in the family, but doesn’t want to deal with his own death. Because I said: We don’t have that much money, the idea came up “I keep the land, you build the house, I grant you a right of first refusal in case of my death.”
Exact words: I can’t inherit it to you, since you are only my nephew and then you would pay a lot of taxes, so for him the subject of “inheritance tax” was closed.
That’s the whole story.