> A monthly stipend probably does more to raise prices than anything useful, unless you also pair it with regulation to stop the wealthy and powerful from taking it all for themselves. And at that point you could have just done those regulations without UBI.

Yes largely correct, but more specifically than "wealthy and powerful," I am referring directly to the landed class, wealthy or not. This type of infusion will ultimately be baked into the cost of land, which will propagate up to rent, then up to wages, then up to goods. The gains will accrue almost entirely to the landed class in the form of higher land rents with no symmetrical increase in costs because land itself does not incur costs.

> Do you think a few lump sum payments over a citizens lifetime would have the same effect? Maybe some large sum paid when you reach age of majority and then again at retirement?

It wouldn't have the same effect but it'd have an analogous effect in the localized markets in which those subsidies are applied. For example, you'd expect the price of land (and so rent → wages → goods) to increase where retiring people congregate. But it'd be less harmful to the exact degree that the subsidy itself is less broadly "helpful."