How much does UBI cost?

I'm curious to know, how much does the concept of Universal Basic Income, or UBI, actually cost to implement and sustain on a national or global scale? Are there any estimates or studies that have been conducted to determine the financial implications of providing a basic income to every citizen, regardless of their employment status or income level? And what factors would contribute to the overall cost, such as the amount of the basic income, the size of the population it covers, and the economic conditions of the country or region in question?