Soil survey even if I don't build a basement?

A soil survey is carried out based on test pits or, preferably, by percussion core soundings. These are placed distributed across the property. If you don't know where the house will be located, you should, if in doubt, do 2 additional soundings, but this extra cost may be justifiable. Besides, the soil on an 800sqm plot will hardly change so much that it cannot be assessed with a handful of soundings.

Best regards, Jann

The cheapest offer I received is just under 1000 euros including tax.

Yes, that roughly fits. It also varies depending on the location in the FRG. My estimated 750 was net, so I think it roughly matches. The market is currently (at least here) still saturated.