Something of token
law usually requires that there be consideration
on both sides of a bargain
-- that the parties are exchanging something of value -- before the contract is enforceable. A court won't enforce a promise
to make a gift. While the courts demand some sort of exchange, they won't inquire into the actual value
of what is exchanged -- hence a contract backed by "peppercorn consideration" is enforceable.
The modern peppercorn tends to be "for one dollar and other good and valuable consideration," often seen in real estate transfers among family members.