Agreed with all above posts, A '57 S.C. $1 is arguably one of the most common S.C.s out there. You can even still find them in circulation once in a blue moon.
For Circulated examples ranging from Fine to Extra Fine, they are only worth 1.25 to 3.50. In UNC grades, perhaps $5 or $6 max. Unless it was in a nice Third party holder and rated at Gem, then I wouldn't pay more than $6.00.
Of course errors and star notes command a premium and star notes can fetch up to $25 in AU or UNC grade. Only GEM or higher star notes will exceed that amount usually. For example on
ebay recently a PMG 64 '57 star $1 sold for $22 while a PCGS 67 sold for $99.
I hope that clears things up.
Honestly, if you wanted one, just bid off one in
ebay.