It sounds like you’re suggesting preemptively increasing sales taxes on luxuries to prevent richer people buying them with their UBI and thus pushing the prices

It sounds like you’re suggesting preemptively increasing sales taxes on luxuries to prevent richer people buying them with their UBI and thus pushing the prices up. The net is the same, prices including sales tax (which everyone pays anyway) go up. If this is an attempt to fund UBI with sales taxes on luxuries (and I’m speculating here) then this could be achieved with progressive taxation - cut income tax for the poor and increase it for those who would be buying the luxuries. I don’t subscribe to the view that this is necessary to support UBI though. Most of it, outside of the well off will get spend on basics anyway. More of a concern for me would be employers cutting wages.