Depends on what you're talking about. Cents (not really "pennies" even though that's the term we all use) have been made since 1792 so there are many specific coins that are highly valuable. One of the more valuable regular-issue Lincoln cents is the 1909-S (San Francisco) coin bearing the designer's initials VDB on the reverse, but there are also many cents from the first couple of decades of the last century that sell for tens of thousands of dollars if in uncirculated condition. Then there's the famed 1943 cents that were minted in error on copper planchets (blanks) left over from 1942, at a time when the Mint had switched to zinc-plated steel due to wartime needs. These have sold for well into 5 figures. If you want to go back to the days of large cents, these can sell for over $100,000 depending on the date and type. See the Related Link "PCGS Large Cents" to the right for some examples.
The highest know price ever paid for a 1 cent coin is 1.7 Million dollars for the only known example of a 1943-D copper Lincoln cent.
the most valuable is the penny in the us has a head on the front and back hope this helped :) :) :) :) :)
As far as general circulation coins are concerned, easily the most valuable Australian Penny is the 1930 Penny and the most valuable Halfpenny would be the 1923 Halfpenny.
Penny
Assuming you mean Wheat penny's, the 1909-S V.D.B., 1914-D & 1931-S are the icons of the series.
1937 penny
A 1943 penny made of copper that's worth $20-40k circulated.
The 1943 Denver copper cent. It was recently sold for 1.7 million US dollars.
The Queen Victoria, penny-red, plate 77, one penny stamp.
The rarest and most valuable Lincoln cent that isn't an error is the 1909-S with VDB on it. The rarest and most valuable error Lincoln cent is the 1943 copper penny.
The 1909-S V.D.B.
1970-S
The most valuable ones are the 1943 copper penny, and the even more rare 1944 steel penny.