Earlier quoted context omitted.
Taxes have to go up to pay for this so there isn't actually more money supply than there was before, it's just distributed differently.
That doesn't mean prices won't change because of it. As a simplified example, let's say poor person A is renting an apartment from rich person B for $500/month. The new system gives everyone $500/month basic income, but to pay for this rich person B has to pay $1000/month more in tax (of which he gets back half as basic income), while poor person A doesn't pay more tax. So essentially poor person A is getting $500/mo…
Prices might go up a bit, but not by that much. The poverty rate in the United States is about 15%. That means that, assuming that the cost of that $500/mo will be spread (unevenly) across the other 85% of the population, or a bit under $100 per taxpayer. That also assumes that the mincome program would exist alongside existing welfare programs, where in reality it would most likely replace them.