WordNet records no synonym and no antonym for bill of goods. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
communication (written or spoken) that persuades someone to accept something untrue or undesirable
“they tried to sell me a bill of goods about a secondhand car”
Synonyms, antonyms and the broader and narrower relations for bill of goods come from Princeton University’s WordNet. Full sources and licences.