All Franklin half dollars were made of 90% silver, but 1957 is not a rare year. In lower grades the coin's value is mostly determined by the value of the silver it contains.
Look on the back of the coin to see if there's a small mint mark letter just above the Liberty Bell. It may be blank or there may be a D.
Numismedia lists the following approximate retail values as of 07/2014:
Circulated:
Very worn condition - $11.50
Moderately worn - $11.85
Slightly worn - $12.19
Almost no wear - $14.40
Uncirculated:
No mint mark (Philadelphia): $16.80 to $720.00 depending on quality
"D" mint mark (Denver): $16.80 to $2670.00
You have a Franklin half dollar - a 1957 proof coin is worth around $25.00.
US$1.25
There were no 50.00 bills in 1957. Your answer is zero.
50$
Value is for the silver about $2.50
You have a Franklin half dollar - a 1957 proof coin is worth around $25.00.
There was no silver dollar in the US made in 1957. It might be a half dollar. These are usually worth about $10-15.
US$1.25
There were no 50.00 bills in 1957. Your answer is zero.
50$
A US half dollar with a date of 1979 is a Kennedy half dollar not a liberty half dollar. The coin has no silver and is only face value.
It has a metal value of about $10.
Value is for the silver about $2.50
All silver certificates printed from 1928 to 1957 had blue seals. Please see the question "What is the value of a 1957 A US 1 dollar silver certificate?" for more information.
About $4-5
50 cents.
a half dollar