Which is available already 'in an early Beta' version.



Free, now = Tatra.



Small-change, now = AH64, Cessna, Tatra, plus sandbox features (road building, object creation and placement), and latest development 'releases' of new features such as grass and 3d trees as they happen... these 'features' will eventually filter down to the Free version, but this is updated less frequently and more conservatively.



'A bit more', later = the same as 'small change' but once Anteworld "the game" is completed, ie non-beta at some time in the future.



You get a discount in return for being a guinea pig/adding input to the development process/beta testing/seeing an advance sneaky-peaky... against a possible risk of losing 3-4 "beers"