I'm not opposed to the idea of UBI, but it doesn't really solve any problems here, it just adds massive political and logistical complexity that would essentially doom any possibility of reforming the tax code.

In this thread, we're discussing how to ameliorate the regressive aspects of sales taxes. Poor people spend most of what they have, so they are subject to proportionally more sales taxes than rich people who spend very little of their vast accumulated wealth on goods subject to those taxes.

The initial, flawed response to this issue would be to construct some "massive political and logistical complexity" in order to track everyone's income and spending and family situation and lots of other stuff too and calculate their VAT refunds based on some formula. The much simpler solution is to just give everyone the same amount of money. Poor people will spend some portion of it on sales taxes, and they'll use the rest for other purposes of their choosing. Slightly richer people will spend all of the UBI on sales taxes but will come out even. Slightly richer people will be able to offset some portion of their sales taxes. Really rich people won't even notice they got a UBI.

Perhaps you really meant that "massive political and logistical complexity" is required to get anything through the legislative process? After all, the more complicated it gets, the more places lobbyists can hide loot for their employers.

One of the things that worries me with UBI is that the somewhat-better-off people without a moral compass- for instance, slumlords- will raise rent and eat really far into other people's UBI because they know everyone gets it and needs a place to live, thus keeping them from being able to save up to afford even a modest "starter home". Like GPU scalpers, they provide very little value and charge a lot for their services. There's a small group of people in my town that really do the poor in via rent already without so much as a care about the quality of housing they provide, and I fear that one of the unintended effects of UBI is that the slumlord class will get a ton more money without doing anything to improve other people's lives.

TL;DR: my fear with UBI is that unscrupulous people will do unfair things like significantly raise rent to eat into other people's free money thus leaving the poor in the same spot, more or less.

It's true that the spending of the poor tends to be concentrated on the "basics": food, housing, transportation, childcare, utilities. Such a situation is inherently subject to more pricing risk. Relatively wealthier people might forego cable TV for six months in order to pay for unexpected car repairs, but that wouldn't be an option for someone who doesn't have cable TV in the first place. Still, your objection has it backwards. Yes, the poor face a relatively limited range of choices in how they can live in an arbitrarily unfair society like ours. However, increasing the income of the poor increases their choices, period. We don't know in advance how exactly they will react to this increased choice, but it's extremely unlikely that their reaction will be to give all the extra money to the same asshole landlord. A more reliable car might allow a family to live in a completely different neighborhood. Working a single job instead of two might allow a parent to spend less on childcare. And so on. Poor people are humans with imagination, not rent-payment-maximizing automatons.

I don't claim to know anything about your town, but I've lived lots of places and in general, in order to really fuck people over the bastards first have to limit their freedom somehow. Are there only certain parts of town in which the poor are allowed to live? Has public transportation been limited in arbitrary ways? Do zoning regs or HOAs enforce impractical restrictions on housing? Would it be OK if your neighbor parked a mobile home and camper behind her house for her recently-divorced sister-in-law plus five kids? What if her nephew and his girlfriend also moved out back?