If you check eBay, a 1934 $20 dollar bill would cost around $25 (circulated) up to $85 (circulated).
But as per Coinsite.com, U.S 1934 twenty dollar notes are not yet valuable, especially if they have been circulated.
An uncirculated note would bring at least a $10 premium. These notes were made for a long period of time and were replaced by the 1950 series of Federal Reserve Notes. A small letter next to the date (A-D) would allow knowing the approximate date range.
They are bound to become scarce over the next ten years as they are replaced by the new $20 design.
However, there are a few characteristics that make some 1934 $20 Federal Reserve Notes more valuable than others. Here’s a few thing to look for:
• Any 1934 or 1934A note overprinted “HAWAII”
• Star Notes, that is notes that have a star next to the serial numbers. They are replacement notes for notes that were destroyed at the Bureau of Engraving.
• In 1948 the White House that appears on the back of the $20 1934C note was changed. The new version shows 2 more chimneys, a second floor balcony and different and larger trees and bushes.
• Though not considered valuable yet, the 1934 $20 Minneapolis Federal Reserve note is scarce and has the lowest number printed of all the $20 1934 FRN issues.
• For the 1934A $20 issues, Atlanta FRN (less than 6 million notes printed), Dallas FRN (only about 2.5 million notes printed and the Philadelphia FRN (less than 4 million made) should be put away for a few years. These will be considered scarce or rare in the future.
Anyone involved in numismatics is especially aware of the scams that are out there these days. Fortunately, most scams are related to coins. Fake collector coins and precious metals scams are worse today than ever before.
Here's how to avoid currency scams on eBay and Craigslist shared by Antiquemoney.com.