In general, a 1934 C US $20 bill in circulated condition can be worth around $100-$200, while an uncirculated bill can be worth significantly more, potentially several thousand dollars.
However, the actual value of a specific 1934 C US $20 bill can be influenced by various factors, including its grade, scarcity, and overall desirability among collectors.
To determine the accurate value of a 1934 C US $20 bill, it is advisable to consult with an expert or visit a reputable coin or currency dealer.