What is the value of a 1957 A US silver certificate?

Answer 1

You didn't provide a denomination, but only $1 bills were issued as 1957 silver certificates. Despite their age they're common among collectors. As of 03/2015 they retail for about $1.25 to $1.75 in average condition. A nice uncirculated one might go for $3 or so.

Blue Ink

From 1928 to the late 1960s the US issued several different types of paper money. Different seal colors were used to make it easy to tell the bills apart:

• Federal Reserve Notes (what we have now) : green ink
• Silver certificates : blue
• Gold certificates : gold
• United States Notes : red
• Special WWII currency : yellow or brown

Serial numbers: Serial numbers rarely help to ID a bill or affect its value. They're counters and an anti-counterfeiting feature.

Redemption: At one time silver certificates could be redeemed for a dollar's worth of silver, but that practice was suspended back in 1968.

Withdrawal: Silver certificates have never been formally withdrawn, but the last ones were printed in the early 1960s (despite the 1957 date) so it's almost impossible to find one in circulation today.