How much is a 1922 twenty dollar gold coin worth?

The type of coin you are referring to is the Saint Gaudens $20 Double Eagle coin. It was minted at two different mints: Philadelphia and San Francisco. The value depends on where it was minted and what condition the coin is in.

According to USA Coin Book, these are the typical values:

Philadelphia (no mint mark): About $980 for a coin in Very Fine condition and $1050 for a coin in MS60 mint condition. A choice uncirculated MS63 coin is worth about $1325.

San Francisco (small "S" mint mark): About $1020 for a coin in Very Fine condition and $2150 for a coin in MS60 mint condition. A choice uncirculated MS63 coin is worth about $4350.

Note: The price of gold is highly volatile and the value of these coins will also fluctuate by a great deal depending on how valuable gold is at any given minute.

View the links below to see more prices for other intermediate conditions of the coin.