C# 2D platformer: How to have player always face center?

I'm building a 2D platformer where I want the player to always face 0 on the x axis.

I tried it by making my player flip with transform.localScale when position.x <0. But my player keeps flipping back and forth when the condition is met (on the left side of the 0 point).

I tried using a bitflag, but not working... What am I doing wrong? (Highly descriptive answers about the why's and how's are much appreciated as I've only started learning Unity and C# a few days ago)

 public Transform flipCheck;
 private bool flipped = false;


 // Use this for initialization
 void Start () {

 }


 void FixedUpdate() {

 }


 // Update is called once per frame
 void Update () {
 

     if (gameObject.transform.position.x < 0 && !flipped) {

         Debug.Log ("player is facing right");
         transform.localScale = new Vector2 (transform.localScale.x *-1, transform.localScale.y);

     }

     else {
         Debug.Log ("player is facing left");

     }