The trillion dollar coin debate has inspired a lot of chatter about legal tender, not all of it correct. The best source on the meaning of legal tender is Dror Goldberg (the same Dror Goldberg from my Yap Stone post). His paper, Legal Tender is short and concise. Give it a read. This post is largely based off his work.
First off. If someone offers to pay you in legal tender, say a US platinum coin, are you obligated to accept it? The answer is no.
When a medium-of-exchange is denoted as legal tender, that means that it must be accepted in the discharge of certain types of debt. If you are engaged in an exchange with someone that doesn't involve the settling of debts, then legal tender laws don't apply. For example, say you walk into a corner store and offer to pay for cigarettes using legal tender platinum coins. The store owner can legally refuse to accept the coins. After all, the two of you are not settling debts—you're engaging in a spot transaction. The owner is on the right side of the law in requiring payment in, say, peanuts. Either pay him in peanuts or walk out of the store without your smokes.
According to Goldberg, legal tender laws start with non-spot transaction—those transactions in which goods & services are provided prior to final settlement, thereby creating a debt. Legal tender laws require that a creditor accept legal tender as settlement for most types of debt contracts (not all, see next paragraph). What qualifies as legal tender? In the US this includes all United States coins and currency, as well as Federal Reserve notes. In Canada, coins produced by the Royal Mint and notes issued by the Bank of Canada are legal tender (see the Currency Act). Private bank deposits are not legal tender in the US or Canada, nor are traveler's cheques or credit cards. Creditors needn't accept cheques or credit cards.
Creditors can structure contracts to avoid the obligation of accepting legal tender. All it takes is that both parties to a debt contract agree ahead of time that some alternative medium will be used to settle the debt. Say a debtor and creditor have agreed to settle three months from now in bitcoin. If after three months have passed the debtor offers to settle with a legal tender platinum coin, the creditor can refuse to accept the coin since the contract specifies BTC. Private agreement trumps legal tender laws.
Even if no alternative media has been chosen to discharge a debt, in certain situations a creditor can still refuse legal tender. In Canada, for instance, the Currency Act specifies that while $2 coins (toonies) are legal tender, they need not be accepted in the settlement of debts over $40. If a debt is larger than $25, the creditor can refuse twenty-five $1 coins (loonies). In India, a half rupee coin is only legal tender for debts less than ten rupees, which means that a creditor can refuse to accept more than twenty half-rupee coins. (See this RBI page.)
Over the years, governments have set some odd commodities to serve as legal tender. In his book Legal Tender (1903) Samuel Breckenridge notes that in 1631, the governor of Massachusetts declared that corn was to pass in payment for all debts at the market rate, unless money or beaver had been stipulated in the contract. Breckenridge goes on to write:
A little later bullets were ordered to be taken, being rated as equal each to a farthing, though no man was to be forced to take more than 12d in any one payment in this form. In 1643, likewise in Massachusetts, wampum [shell money] was given the debt-paying quality within the value of 40s at the rate of four pieces of black or eight pieces of white to a penny. Similar legislation was enacted in Connecticut and Rhode Island. In Virgina and Maryland tobacco was the commodity most universally desired, and so, in 1633, Virginia enacted that, while contracts, judgements, etc., should be reckoned in English money, they should be paid in tobacco. And a century later Maryland made tobacco a legal tender at a penny a pound, and corn at twenty cents a bushel. In North Carolina corn, pitch, tar, pork were also used at specified rates. Thus, in 1715 any one of seventeen commodities named might be used as a legal tender or in payment of taxes. (Pg 53).Here I'm obligated to present the alternative view to Goldberg, of which Breckenridge himself provides a decent example. In his book, Breckenridge adopts the common view that legal tender laws applies to all transactions, whether these be time (credit) or cash (spot) transactions. Writes Breckenridge:
in general, it may be said that both gold and silver coins were a lawful tender; that in cash transactions the buyer, in time transactions the debtor, had the right to select the form of money to be employed. In the case of cash transactions it was found necessary to supplement this law by penal legislation and by legislation regulating prices. But in the case of time transactions, the civil power of the courts was an adequate sanction.Who is right? Here's a quote from the Richmond Fed that settles the matter, at least in its modern US context:
However, no federal law mandates that a person or an organization must accept currency or coins as payment for goods or services not yet provided. For example, a bus line may prohibit payment of fares in pennies or dollar bills. Some movie theaters, convenience stores and gas stations as a matter of policy may refuse to accept currency of a large denomination, such as notes above $20, and as long as notice is posted and a transaction giving rise to a debt has not already been completed, these organizations have not violated the legal tender law.It would seem that Goldberg is correct. In spot transactions—those in which a debt hasn't been created—legal tender laws don't apply. No one needs to accept your trillion dollar coin or Federal Reserve note. At least not over the counter.