The word "bill goods" refers to the process of invoicing or charging for goods sold. Antonyms for this phrase include "free goods", indicating that no payment is required for the goods, and "donate goods", indicating that the goods are being given away for charitable purposes. Another antonym could be "return goods", indicating that the purchased goods are being returned to the retailer or manufacturer for a refund or exchange. Alternatively, "stolen goods" could be an antonym, indicating that the goods have been obtained without payment or permission. These antonyms reflect opposite situations to the process of billing goods, where payment and ownership are either absent or contested.