1957 silver certificates are quite common among collectors. Huge numbers of these were saved when the government announced that the series would be discontinued.
As of 03/2010, a circulated 1957 A bill retails for $1.25 to $1.50 but a dealer is unlikely to pay more than face value (1 dollar). A nice uncirculated one might sell for around $3 and a dealer might pay about $2.
It's normally not necessary to provide a bill's serial number. Serial numbers are counters and a security feature but rarely affect a bill's value or help to identify it. Some collectors will pay extra for numbers with a
special pattern, e.g. 12345678, or low numbers such as 00000015.
1957 is the single most common date for $1 silver certificates. That was the last series date printed before the denomination was reissued as a Federal Reserve Note beginning in 1963, so huge numbers of them were saved as keepsakes and hoped-for rarities. However there are still so many available that more than half a century later an average-condition bill retails for only about $1.50.
$1.25 to $1.50 if circulated, about $3 if uncirculated and unfolded. Series 1957 silver certificates are common among collectors. That was the last series year for $1 silver certificates, so a lot of them were saved.