I would only do crowdfunding with an absolutely watertight plan. Let's see what the more detailed calculations show.
(Edit: Oh almost posted a link Sorry had to search myself on Immo Scout. Just look for plot areas in the East and you will definitely find something.) Although at the middle of nowhere, 10€ per sqm ;P I have also seen plots for free in the East. Even here in Hesse you can find a small plot for a few thousand € and the development costs are already included. The 10 years were not really meant seriously, then I would only be allowed to lay 2-3 bricks per day. As I already wrote, I already own the interior fittings. Material costs are not very high if you do everything yourself. Transport costs, on the other hand, are likely to be a real problem. I totally forgot about them X_X especially if I don't have anything nearby to collect. The most expensive equipment is the excavator with 500-1000€. Depending on what can be found in the soil on the property, you can also save some money. Clay or peat, for example, would be a real jackpot. Even if I roughly calculate everything and round up extremely, I don't come up to 25,000€. Of course, if I have, for example, the foundation done, 10,000€ are gone immediately. Even if I do everything with reinforced concrete and insulate with aerogel mats, fulfill all requirements and whatever, then the whole thing costs 50,000. The little hut will never cost 200,000.
However, I have also read a lot of negative things about the Earthship by now. Car tires, for example, are absolutely not suitable. The wet soil is supposedly not so good for insulation effect in Europe either. PET bottles absolutely must be dry inside. That means just slapping soil inside is unfortunately not an option. + The 0.20 cents make the things a bit less attractive again. They are only really worthwhile if they achieve the advertised insulation performance. I definitely have to test the insulation effect of the PET bottles in a small experiment. Sand seems to insulate very well with 0.7. I definitely have to test the insulation effect of the PET bottles in a small experiment. Sand seems to insulate very well with 0.7.
I am also considering that if I can get natural stone somewhere for free, just like with retaining walls, to pack the stones into a grid and fill the whole with bentonite. Natural stone has poor insulation performance but with the greenhouse around it maybe that's not so bad.
P.S. Is it actually correct that posting links = ban? Or was that just a joke at registration? After all, the link function is still available.