What are the best counter openings to the King Pawn Opening?

Sicilian 1...c5 and French 1...e6.

What he said i prefer the falkbeer counter gambit

For more about various specific individual possibilities, one can look at:
Starting Out: Open Games
https://web.archive.org/web/20140626232452/http://www.chesscafe.com/text/hansen134.pdf
Starting Out: Ruy Lopez
https://web.archive.org/web/20140627024240/http://www.chesscafe.com/text/hansen53.pdf
The Petroff: Move by Move
https://www.newinchess.com/media/wysiwyg/product_pdf/7530.pdf
Starting Out: The Sicilian
https://web.archive.org/web/20140627122350/http://www.chesscafe.com/text/hansen123.pdf
First Steps: The French
https://www.newinchess.com/media/wysiwyg/product_pdf/7611.pdf
Opening Repertoire: ...c6.
https://www.newinchess.com/media/wysiwyg/product_pdf/7673.pdf
The Pirc: Move by Move
https://www.newinchess.com/media/wysiwyg/product_pdf/7604.pdf
First Steps: The Modern
https://www.newinchess.com/media/wysiwyg/product_pdf/7700.pdf
The Scandinavian: Move by Move
https://web.archive.org/web/20140626232217/http://www.chesscafe.com/text/hansen171.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/7270.pdf
My First Chess Opening Repertoire for Black by Moret
https://www.newinchess.com/media/wysiwyg/product_pdf/9050.pdf
The Alekhine Defence: Move by Move
https://www.everymanchess.com/downloadable/download/sample/sample_id/69/

Whoa ..... Are these all against the king pawn opening??

1...e5, 1...c5, 1...e6 and 1...c6 (in no particular order) are the main defenses to 1 e4. The "second tier" encompasses 1...d5, 1...d6, 1...g6 and 1...Nf6 (again, in no particular order). 

One can get some idea of the range of possibilities after 1 e4 by looking at: http://www.gambitbooks.com/pdfs/A_Simple_Chess_Opening_Repertoire_for_White.pdf

As Black, one can pick one reaction to 1 e4 and pretty much ignore the others. If you are going to play 1 e4 as White, you may face a lot of possibilities, but facing a defence is not the same as knowing how to use it.

1...e5, 1...e6, 1...c6, 1...c5, and 1...d5 are introduced in Discovering Chess Openings by GM John Emms.

"... For beginning players, [Discovering Chess Openings] will offer an opportunity to start out on the right foot and really get a feel for what is happening on the board. ..." - FM Carsten Hansen (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf

In My First Chess Opening Repertoire for White by Vincent Moret, one can find games illustrating various reactions to 1 e4.
https://www.newinchess.com/media/wysiwyg/product_pdf/9033.pdf
https://www.chess.com/article/view/how-to-understand-openings

At your level of play - and at most levels of play - the games are usually one because one player gives up more pieces than the other, not because of some clever counterattack.  I would concentrate on openings that allow you to make threatening moves and to overprotect your pieces where you can see possibilities for long term strategies.  1 e4 e5 followed by a 2 N's defense works, 1 e4 c6 and 1 e4 e6 and also works.

Sometimes, I think we are all one.