It's worth at least $20. Without knowing the series (date), it's impossible to give a more specific estimate.
$50
There were no series letters on any 1929-dated US bills. A large "G" indicates that the bill was distributed through the Chicago Federal Reserve District. There's more information at the question "What is the value of a 1929 US 5 dollar Federal Reserve Note?"
$12 to $15, assuming average wear.
Without knowing details like the series (date) and condition, the best possible answer is that it's worth $20.
A date is needed. Please see the question "What is the value of a (date) US 20 dollar bill?" for more information.
In worn condition, face value only. If only slightly worn, $8 or so.
More information is needed, like series date, condition, and is it a Federal Reserve Note, Silver Certificate, Demand Note, or what?
There were no series letters on any 1929 US bills. You may be referring instead to the Federal Reserve District letter; "G" indicates your bill was distributed by the Chicago district. There's more information at the question "What is the value of a 1929 US 100 dollar Federal Reserve Note?"
As of 09/2008 auction prices are around $24.
Face value only.
The 1934 100-dollar bills ended with Series D. A note in good condition, with little wear can be worth about $140.
A denomination is needed. Please look for questions in the form "What is the value of a 1928 A US [denomination] dollar Federal Reserve Note?" for specific information.