Costumes stay Halloween's biggest category as US spending holds at 13.5 billion dollars

US consumers are expected to spend 13.5 billion dollars on Halloween this year, and costumes remain the largest single category in that total at 4.4 billion dollars, ahead of decorations at 4.3 billion and candy at 4.1 billion, according to the National Retail Federation's annual survey conducted by Prosper Insights & Analytics.