What is the value of a 1991 Silver Eagle dollar?

If you have the proof eagles in the Mint-issued plum-colored packaging, then the 1991 is worth about $40 and the 1992 is worth about $35 If they are anything else, it's a standard bullion piece but not struck as a proof, it would be worth a bit more than the current spot price of one ounce of silver. That price changes daily, so you'd have to check it in the financial pages of your newspaper or on-line at a financial site like CNN Money (among many such sites).