Inherited property with a prefabricated house built in 1978 - what now?

The neighbors are almost all interested. One says he has a privilege because he made an arrangement with my grandmother. They had a close relationship. However, there is neither anything in writing, nor did we know anything about it. I would like to handle this fairly towards all interested parties. And of course also achieve a reasonable price. For that, I would need a "starting price" at best. Maybe we just need a real estate agent for that?

well, you can inform him about your purchase intentions. let's see what he says. not that he causes trouble when your interested parties come. that could possibly be detrimental to the sale price if the neighbor starts ranting :)

Do it like this if you want to sell. Agent, determine the value, then tell the agent that neighbor xy is now being offered the house by me at this price, because of grandma and such. He pays no commission if he buys, because you did not recruit him. You, agent, please start at the same time next week to gain customers. Whoever strikes first gets it. This is how you also inform Grandma’s buddy. Then he should behave accordingly. And you have zero stress. Karsten

The basement could increase the price, reduce the pollutants "upstairs."

Basement means: 1) house connections: done.; 2) storage room: done.; 3) site work for the floor slab: done. If you don’t like the stair position of the basement: in the worst case, redo all ceiling sections of the basement or create an outside access. So the existing basement is at least everything you would need as preliminary work for the floor slab, plus storage room and the house connections are already there.

As for the "upstairs": pollutants are often in the cladding, not in the construction. More DIYers dare to "strip" these than you might think; and since entire prefab house generations are affected, there are already specialists for this. In the worst case, tear everything down and dispose of it, then "only" the basement remains.

For that, I would ideally need a "starting price."

You get that from the neighbor who thinks they have the verbal right of first refusal. And the standard land value for comparison is provided by a publicly accessible map (see the geoportal of your federal state).

Ask real estate agents: that joke is good. A real estate agent needs three failed hamburger tests, a police clearance certificate free of property and financial crimes, a clean shirt, and a used cellphone. Of course, there are good apples in this profession – but before you find one, you will have had success with your sales project yourself.

Take a look at a real estate portal: the click to the "floor plan" leads to a city map, then object photos taken with the cheapest camera, and so on. I always read the most careless offers from genuine professionals ;-)

Such birds bring you zero shortening of the time between listing and sales success, a value assessment at the average of what a counter survey yields, and want to earn a commission even if the buyer didn’t come from their seed.

My experiences with agents are different and significantly better.

And the standard land value for comparison is provided to you by a publicly accessible map (see the geoportal of your federal state).

I meant more precisely: there you see a value for the square meter of building land in this plot in its undeveloped state. Then you hypothetically assume this undeveloped state and inquire about what the earthworks for a level slab (excavation, embankment, slope stabilization) would cost. The buyer saves that with the existing basement. Whether the demolition with debris disposal offsets that more or less, you leave that for the interested parties to assess.

My experiences with real estate agents are different and significantly better.

I know better ones too, but they usually don’t take fixer-uppers into their portfolio. The good agents gladly leave the less attractive properties to the less capable colleagues.

So actually, the value should be composed as follows:

Land value benchmark (as of 2016)
+Value increase since 2016
+Nice location
+Basement
+Double garage
-Disposal of prefabricated house

The question arises how to evaluate the individual points.
Perhaps the disposal is offset by the basement and the garage.
That leaves value increase and location.

What do you think?