It all depends on where it was minted and what condition the coin is in. Typically, a coin in Good condition is worth about $5 on average. Uncirculated coins are generally worth about $20 and higher...
Please check your coin again. It's either not 1934 or not Franklin. Halves dated 1916-47 carried the Walking Liberty design. Franklin's image was on the half dollar from 1948 to 1963.
Franklin half dollars are not rare or even scarce so if the coin has any wear at all value is just for the silver about $6.00. Uncirculated coins can be more at $10.00-$15.00
There are 20 coins in a roll of half dollars. Their value depends upon which mint produced them and the condition of each coin. Giving an estimated value of the roll with several hundred dollars...