Average circulated coins are 3 to 10 cents. Uncirculated can be as much as $20.00
No mint mark means it was minted in Philadelphia. On average, it's worth 10 cents.
A denomination is needed, post new question.
From $1 to $7500 depending upon the mint mark and the condition of the coin.
The 1934 Philadelphia ( no mintmark ) Lincoln cent is common. In average circulated condition, values run from 10 to 50 cents.
G isn't a mint mark for anywhere, and you didn't specify which type of coin.
Normally the question has to be asked "WHICH mint mark?". However the only 1934 cents with a mint mark came from Denver so your coin has a D below the date. Most circulated 1934-D cents are only worth a small premium - 15¢ or so in worn condition up to a half-dollar with only moderate wear. However nice 1934-D cents in almost-uncirculated or uncirculated condition are scarcer and can be worth $5 to $10 depending on how well-struck they are.
One Billion
Mark Gerard was born in 1934.
Mark Wolfson was born in 1934.
The US Mint only makes coins so a bill can't have a mint mark. In 1934, all US paper money was printed in Washington. Since 1990, bills have also been printed in Fort Worth. The "D" on your bill could be at least two different indicators. If the letter is under the date, please see the Related Question about a 1934 D bill. If the letter is inside the Federal Reserve Seal, please see the Related Question about a 1934 Federal Reserve Note.
The 1990 Folger's Coffee car.
1934 mark