PlayerPrefsManager custom this is just a base just copy the pattern and add too for your liking.

PlayerPrefsManager.cs

//
// PlayerPrefsManager.cs
//
// Author:
//       ${ZeredaGames-AKA Thamas Bell} <${thamasbell@hotmail.com}>
//
// Copyright (c) ${2015} ${Thamas Bell}
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using UnityEngine;
using System.Collections;
namespace ZG.Managers.PlayerPrefs
{
	public class PlayerPrefsManager : MonoBehaviour
	{
		/// <summary>
		/// The  The Master Volume Constant
		/// </summary>
		const string MASTER_VOLUME_KEY = "master_volume_";
		/// <summary>
		/// The Master Difficulty Constant.
		/// </summary>
		const string MASTER_DIFFICULY_KEY = "DiffLvl";
		/// <summary>
		///  The Master Graphics Constant.
		/// </summary>
		const string MASTER_GRAPHICS_KEY = "Graphics Settings:";
		/// <summary>
		///  The Master Camera Constant
		/// </summary>
		const string MASTER_CAMERA_KEY = "Camera Settings:";
		
		/// <summary>
		/// Sets the master graphics.
		/// </summary>
		/// <param name="graphValue">Graph value.</param>
		public static void SetMasterGraphics (float graphValue)
		{
			if (graphValue >= 1f && graphValue <= 6f) {
				PlayerPrefs.SetFloat (MASTER_GRAPHICS_KEY, graphValue);
				print ("Setting Quality Setting: = " + PlayerPrefs.GetFloat (MASTER_GRAPHICS_KEY));
				print (EnumGraphics.GraphicsStates);
				print (QualitySettings.currentLevel);
			} else {
				Debug.LogError ("<color=red>Graphics out of ranger</color> <i>(Above 1 and below 6)</i>");
			}
		}
		/// <summary>
		/// Sets the master camera.
		/// </summary>
		/// <param name="camValue">Cam value.</param>
		public static void SetMasterCamera (float camValue)
		{
			if (camValue >= 1f && camValue <= 4f) {
				PlayerPrefs.SetFloat (MASTER_CAMERA_KEY, camValue);
				print ("Setting Camera Setting: = " + PlayerPrefs.GetFloat (MASTER_CAMERA_KEY));
				print (EnumCamera.CameraStates);
			} else {
				Debug.LogError ("<color=red>Camera out of range</color> <i>(Above 1 and below 4)</i>");
			}
		}
		/// <summary>
		/// Sets the difficulty.
		/// </summary>
		/// <param name="DiffLvl">Diff lvl.</param>
		public static void SetMasterDifficulty (float DiffLvl)
		{
			if (DiffLvl >= 1f && DiffLvl <= 4f) {
				PlayerPrefs.SetFloat (MASTER_DIFFICULY_KEY, DiffLvl);
				print ("Setting Diffitulty Setting: = " + PlayerPrefs.GetFloat (MASTER_DIFFICULY_KEY));
			} else {
				Debug.LogError ("<color=red>Difficulty out of range</color>  <i>(Above 1 and below 4)</i>");
			}
		}
		/// <summary>
		/// This Must be 0 and 1 or the volume doesnt work correctly
		/// Sets the master volume.
		/// </summary>
		/// <param name="master_volume_">Master_volume_.</param>
		public static void SetMasterVolume (float master_volume_)
		{
			if (master_volume_ > 0f && master_volume_ < 1f) {
				PlayerPrefs.SetFloat (MASTER_VOLUME_KEY, master_volume_);
				print ("Setting Volume Setting: = " + PlayerPrefs.GetFloat (MASTER_VOLUME_KEY));
			} else {
				Debug.LogError ("<color=red>Volume out of Ranger</color> <i>(Above 0 and below 1)</i>");
			}
		}
		
		/// <summary>
		/// Gets the master graphics.
		/// </summary>
		/// <returns>The master graphics.</returns>
		public static float GetMasterGraphics ()
		{
			print ("Getting Graphic Setting: = " + PlayerPrefs.GetFloat (MASTER_DIFFICULY_KEY));
			return PlayerPrefs.GetFloat (MASTER_GRAPHICS_KEY);
		}
		/// <summary>
		/// Gets the master camera.
		/// </summary>
		/// <returns>The master camera.</returns>
		public static float GetMasterCamera ()
		{
			print ("Getting Camera Setting: = " + PlayerPrefs.GetFloat (MASTER_DIFFICULY_KEY));
			return PlayerPrefs.GetFloat (MASTER_CAMERA_KEY);
		}
		/// <summary>
		/// Gets the master volume.
		/// </summary>
		/// <returns>The master volume.</returns>
		public static float GetMasterVolume ()
		{
			print ("Getting Volume Setting: = " + PlayerPrefs.GetFloat (MASTER_DIFFICULY_KEY));
			return PlayerPrefs.GetFloat (MASTER_VOLUME_KEY);
		}
		/// <summary>
		/// Gets the difficulty.
		/// </summary>
		/// <returns>The difficulty.</returns>
		public static float GetMasterDifficulty ()
		{
			print ("Getting Difficulty Setting: = " + PlayerPrefs.GetFloat (MASTER_DIFFICULY_KEY));
			return PlayerPrefs.GetFloat (MASTER_DIFFICULY_KEY);
		}
	}
}