Cash on barrelhead is a phrase commonly used to indicate the requirement of immediate payment in exchange for goods or services. If we look for its antonyms or opposite terms, we can find phrases like "credit," "deferred payment," and "installment plans." These antonyms suggest a delay in payment, allowing buyers to pay over time, usually with interest. On the other hand, terms like "unsecured loan," "negotiable instrument," and "credit card" could also be considered as antonyms of cash on barrelhead, as they imply borrowing money to make a purchase rather than immediate payment. Regardless of the antonym, it is essential to choose the right payment method according to your financial circumstances and needs.