If you're referring to the $1 coin that was released in early 2007, it's worth face value only. Several hundred million were struck for circulation, so feel free to spend it.
Much more information is needed. Please post a new, separate question with: > The name of the country that issued the bill > Its date > If a US bill, what letter if any is under / next to...
One dollar bill (or any American bill for that matter) = 1 gram.
1,000,000 bills = 1,000,000 grams. 454 grams = 1 pound, so
(1,000,000 / 454) 1,000,000 bills = 2,202.64317 pounds, or about 2 pounds...