No, the entire point of UBI is to literally put $X extra into everybody's pocket. What they do with it after that is up to them.
More importantly, half the people receiving the benefit, by definition, will be making the median income or less. Since wealth correlates highly with income, and the phenomenon of marginal propensity to consume means less wealthy people spend more of their income, most of this money is going to be spent. Since inflation is literally caused by too much money chasing too little demand, that solves the whole "competitive market" issue.
Even more importantly, there are many goods with highly inelastic demand. So, no, as another commenter says, prices of USB cords are not likely to increase, but, if you start putting more money in the pockets of average folks, look forward to the prices of housing, education, food, healthcare, etc. all going up even faster than they are now over time.
More importantly, half the people receiving the benefit, by definition, will be making the median income or less. Since wealth correlates highly with income, and the phenomenon of marginal propensity to consume means less wealthy people spend more of their income, most of this money is going to be spent. Since inflation is literally caused by too much money chasing too little demand, that solves the whole "competitive market" issue.
Even more importantly, there are many goods with highly inelastic demand. So, no, as another commenter says, prices of USB cords are not likely to increase, but, if you start putting more money in the pockets of average folks, look forward to the prices of housing, education, food, healthcare, etc. all going up even faster than they are now over time.