What taxable property or service is being sold?
What is being purchased to tax?
Nothing. The "fairtax" is zero on gov't wages. It is a special rule implemented that creates the tax on gov't wages, not a sales tax. Without the rule, gov't would be able to grow by hiring employees for much less than contracting to private enterprise.
Hence the price (including the "fairtax" of zero if you like) is 23% of the wages.
What taxable property or service is being sold?A taxable property or service doesn't have to be "sold" to be taxed. The tax is applied to "the gross payments for the taxable property or service." Subparagraph A states "The term 'taxable property or service' means ... any service." And "for purposes of subparagraph (A), the term 'service' shall include any service performed by an employee for which the employee is paid wages or a salary by a taxable employer."