Perhaps instead of UBI we should be doing UBE (Universal Basic Expense). Most governments run deficits today so maybe we start with ending those. Here is how it could work:

At the end of ever taxation year, the government calculates its deficit for the year. Divide this by all income earners at their marginal tax rate. Then, at tax time, the tax payer can choose to either pay this or allow it to accumulate at the same rate that the government charges itself. Maybe once we can cover deficits we can start thinking about UBI.