Dave Bonta's poem looks at a coin from one angle after another, and each angle opens onto something else. A coin is "of the realm," real even when a magician pulls it from someone's ear. It has value because it is common: every coin is nearly identical, which is why it can be traded for anything, even "better weather." The same sameness makes it easy to toss, and tossing a coin is also a way of deciding.
Midway, the poem slips from money to language. We "toss" new phrases around hoping they'll "gain currency," and we test their mettle the way someone bites a coin to check it's genuine. So the poem suggests words and money work alike: both are worth what people agree they're worth.
The mood is playful and curious, with a darker note near the end. The coin becomes an "unreal moon" and an "eyelid for a corpse," hinting at the old custom of placing coins on the dead. The final split, "legal / tender," leaves a pun hanging between law and gentleness.