As I wrote in a comment on your first post, it is clear that we want our state to provide some sort of social safety net for those who have no income (we don't want the sick and the old starving and dying on the streets). I do agree that UBI is the right way to go, but it is not cheap.

How expensive then, would a UBI program be?

Well, define Iavg as the average citizen income per month. In that, I include all forms of income, whether it is through work, profit from company shares owned, interest, gifts or UBI.

The average income in the US today is about $7,500 per household and month, so let us use this number. A UBI of $1,875 would be a very modest UBI, it would be very hard for a houshold to manage on that. But it is still 25% of this Iavg. So, to afford this very modest UBI program, we'd need to collect tax (land tax by your system) amounting to 25% of the average income. In other words: the average citizen would need to pay, in one way or another, directly or indirectly, 25% of their income to the UBI program. And that is not including expenses for the military and other services. As your state's only income is land tax, these land leases are going to need to be very, very expensive.