universal basic income is a form of social security system in which all citizens or residents of a country regularly receive an unconditional sum of money, either from a government or some other public institution, in addition to any income received from elsewhere. (Imagine if you will, if the government simply gave every citizen over the age of 18 $35,000 every year. Enough money to cover the BASIC NEEDS of a person.) The free market and labor market still exist, people still work for money, people still buy stuff with money.
Some links if you are curious as to how this works: