 One avenue for non @-@ compliance is the black market . FairTax supporters state that the black market is largely untaxed under the current tax system . Economists estimate the underground economy in the United States to be between one and three trillion dollars annually . By imposing a sales tax , supporters argue that black market activity would be taxed when proceeds from such activity are spent on legal consumption . For example , the sale of illegal narcotics would remain untaxed ( instead of being guilty of income tax evasion , drug dealers would be guilty of failing to submit sales tax ) , but they would face taxation when they used drug proceeds to buy consumer goods such as food , clothing , and cars . By taxing this previously untaxed money , FairTax supporters argue that non @-@ filers would be paying part of their share of what would otherwise be uncollected income and payroll taxes . 
