Additional costs for sloped land with tree coverage

Thank you for your tips and suggestions. That helped me a lot. I was skeptical about the property from the beginning. Very unfortunate. Then the property search will probably continue for now. Unfortunately, money also plays a role. That is what the thread was originally about. I also thought it would be more expensive, I just hoped that it could be done with an additional 50-70k costs or so. Since the property is very cheap, that wouldn’t have been a big deal. But that seems to be more of a bigger issue.

Our property was previously developed - therefore, little earthworks, the high retaining wall is present.
Additional earthworks + filling and compacting driveway + surcharge for thicker retaining wall (house rear wall) and floor slab, surcharge for reinforcement were 17K in 2017.
Thicker floor slab, differently dimensioned beam 15K in 2017.
There is no additional small wall in the outdoor area yet, no excavator bucket filling material included.
The surcharge for driveway, terrain modeling as you marked and support will probably head strongly towards 100K. You have to plan differently, then it will be cheaper.

Then the search for a plot will probably continue for now.

Then it is probably not "The Dream Plot" after all if you give up so quickly. A slope offers great opportunities. However, with this statement

What is the price range for leveling the garden?

you rule out all solutions that are also feasible on a limited budget. A slope calls for building with it, not transforming it into one or more horizontal levels. If you cannot imagine being happy with sloping terrain, your first focus should be on the height differences. If they are over one meter, further consideration of the plot is not worthwhile. Or you open your view to the special charms of a hillside location.

What you might save on earthworks is eaten up by the higher costs of the driveway and on-site development.

I can fully confirm that from practical experience.

I want to build the house "higher" because I want more light and then you have the great view of meadows and fields.

I can also confirm that as an advantage from practical experience.

Especially since the development, the driveway, becomes insanely expensive.

That too... Our plot was much cheaper compared to relatively flatter ones due to the many disadvantages for building. That somewhat offsets the additional costs when you consider the whole project. Plot 25% cheaper, construction 30% more expensive – then it’s actually manageable. Of course, if you want to use the budget intended for a flat plot without cuts for the hillside plot, the 30% remains uncompensated. The 30% is an exemplary estimate that can vary greatly and is no rule of thumb.

Then it probably isn’t "The dream property" after all if you give up so quickly. A slope offers really great possibilities. However, with this statement

you exclude all solutions that are also feasible with a limited budget. A slope demands to build with it, not to turn it into one or more horizontal levels. If you can’t imagine being happy with sloping terrain, your first focus should be on the height differences. If they are more than one meter, further consideration of the property is not worthwhile. Or you open your eyes to the special charms of a hillside location.

Well, everything except the slope pretty much fits. I actually like slopes, because I like my house to stand higher. However, I don’t want to build directly on the street side of this property because then I would be building in a "hole." The street is the lowest point. The houses on the other side of the street are also elevated. Next to me there would be forest and behind that the steep slope. I absolutely can’t imagine that looking nice. Further up, I would have a great view. I will visit the property again today or tomorrow (300 km drive) and think more about it.

I can imagine that my garden or the area around the house has several levels. For example, I can well imagine that in front of the house it is level with the basement and the garden then is level with the ground floor. I can also imagine another level and allowing a slight slope, especially where the trees stand. But I want to actually be able to use my garden as a garden. For parties, sports, etc. And a steep slope is very unfavorable for that.

I can fully confirm this from practical experience.

I can also confirm this from practice as an advantage.

That too...

Our property was much cheaper to build on due to many disadvantages than comparatively flatter ones. This somewhat balances out the additional costs when considering the whole project. Property 25% cheaper, construction 30% more expensive – then it’s actually okay. Of course, if you want to use the budget planned for a flat property without any reduction for the slope property, the 30% remain uncompensated.
The 30% is an example estimate, which can vary greatly and is not a rule of thumb.

The property price corresponds to the standard land value according to the cadastre map, but all other properties (there are no others available in this town) are traded significantly higher. And being at the end of a dead-end street has always been my dream and it is very close to our workplaces (10–15 minutes) and family. We would probably save something between 50,000 and 70,000 euros on the property price compared to other lots. If we could "make it work" with that, I would take the property immediately, but it sounds like such a property is a bottomless pit. That unsettles me.

but it sounds like such a plot is a bottomless pit.

No, it definitely isn’t, because the costs are also plannable for the project. Your original question was how much additional cost you have to expect, and the answers can’t relate to a specific project. So you collect what needs to be considered. Bottomless pit would mean incalculable.

We would probably save something between 50,000 and 70,000 euros on the plot price compared to other plots.

The comparison to the other plots is nice but not budget-relevant for you. If you had previously planned, for example, 300K for the plot and 400K for the house and 100K for ancillary costs, garden, miscellaneous, so a budget of 800K, you have to buy the plot for 200K to end up again at about 800K in the end.

A slope demands to build with it, and not to convert it into one or several horizontal levels.

That is the key. You sensibly build on the slope not the same as on flat ground. Therefore, a "comparison of additional costs" is so misleading. Additional costs compared to what? A house you wouldn’t build there anyway?

I can imagine that my garden or my surroundings have several levels from the house.
...
But I want to be able to actually use my garden as a garden. For parties, sports, etc. And a steep slope is very inconvenient for that.

Here too, it applies to carefully look at the plot as writes and sketch a plan for it. Every slope is different and offers different possibilities. Much can be solved pragmatically and quite inexpensively, some things not. The soil conditions also play a role.

Conclusion: Your specific project must fit the budget. If the plot costs 70k less than planned, that already gives good leeway for it.

We love living on the slope. For us it has fully paid off.